To a casual inspection, this world's biota resembles the Earth/Arda standard, but with a wider slice of evolutionary history than normally exists at one time outside Valinors. The sapient population is in the low thousands, with a stone-age level of technology. The oldest people appear to be middle-aged, mostly much younger, and the sapient inhabitants comprise most of the youngest generations of a larger population of which the older generations are non-sapient hominids.
"Not much hair, big heads, smart? The things that make people born now mostly different from people born before, that isn't being young."
"Ah. Hm. So, on worlds we've learned about in the past, that happens only very, very slowly. Modern people are descended from less modern ones, but with many generations separating them."
This is apparently a pretty surprising claim.
"What are... 'Worlds'?"
"Worlds are a kind of place. Bigger than all the land you've ever seen, bigger than all of that land plus a few more lands the same size with water between them even bigger."
"You travel between those?
If people from your homeland have been very modern for a very long time, that might be why you have so much technology.
In your homeland, do animals also only evolve very slowly, or just people?"
"Animals also evolve only very slowly, though they can be bred fast if they have short generations."
"Huh. Why might here be different?"
"I don't know, it's very interesting. Especially since it means we have no idea what your grandchildren will be like!"
"Nor do we! One-day we'll find out."
"Star thinks they'll be even smarter than we are, but animals and plants don't always change the same way generation-to-generation, right?"
"I think they'll probably be even smarter than we are. We've been changing the same way for at least three generations."
"On most worlds, the changes happen because whichever plant or animal or person has the most children gets to contribute more to the next generation - so individuals that are infertile, or sickly, or not good at having a lot of children for any other reason, have fewer children, and fewer grandchildren. But it takes many many years for this to have any noticeable big effects."
"Hmm. That's puzzling, I can't think how to say how."
"It takes a long time to notice it happening, too, in worlds like that. Here it's very obvious that it's happening but not clear how!"
The puzzled person has figured out words for what was puzzling her, now.
"If people in other worlds don't evolve for the same reason we do, why do they look the same afterwards? Does our world... look at other worlds and copy them?"
"That would be my guess, but it's definitely very weird and we haven't found any other worlds that definitely seem to be doing that."
"The aurochs-followers are trying to kill off the fiercest aurochs in their herd and spare the gentlest ones, right? We should ask them if aurochs start evolving to be gentle"
"The sort of evolution other worlds have must work here too, though, it might be hard to tell our sort apart from that."
"We should be able to tell it apart because our sort is much faster, though."
"Maybe someone will want to bring a plant or animal that breeds very quickly here and see what happens if they breed it in different ways. In the meantime, we're not scientists, we're envoys! We're here to help you out with whatever you need and tell you about the other worlds out there - what do you most want to learn or get?"
"Well, we'd really like to be able to bring back the dead, and to learn to use healing magic ourselves, and to learn to reverse and prevent ageing. Being able to travel like you do also looks very useful."
"It sounds like- you have so much technology you can't just list all of the best stuff? If you have ways to protect us from being injured by enemies and wild animals in the first place, that would be very good. If you have ways to let us get food and water more easily during dry years, that would be very good. If you have a way to make pregnancy and childbirth less painful, that would be very good."
"What are other worlds like? How do people in other worlds live? How many other worlds have you been to?"
"The magic you can buy with money - do you use money here? And the injury prevention we - mostly do by not getting into fights with enemies or wild animals in the first place. Food and water and improving pregnancy and birth are all technology, not hard to come by." He can show them pictures of worlds he has been to - born on this ones, live on this one, worked here for a while, went there on vacation...
"If we use money here, we don't call it that. What is it? How do you keep enemies and wild animals from attacking you? Can you teach us your technology for getting food and water and improving pregnancy?"
The pictures of other words are amazing! Those landscapes are bizarre and spectacular! Those are so many people in one place! Look at all the different sorts of people!
One of children will ask if they can go to see those places themselves. Another of the children will point to some of the weirder-looking people and ask what they are.
"If you called it something else our translation magic would almost certainly work on it. It's a thing that everyone agrees represents the option to trade for things. So I spend money to buy something from one person, and then they can spend that money to buy something from another person, instead of trading or doing favors. You make peace with your enemies and live places wild animals don't, and if that doesn't work, you can use magic to keep them away from you. And of course, though the things you'll be able to do yourselves and the things that will work fastest today are different."
The kids can go on the bus like anyone else once there are stations here! That's an Andalite, that's a Klingon, that's just an angel with a really outré look...
"Well, then it sounds like we need a way to get enough money to buy healing and resurrection and protection from you. Or a way to do the magic ourselves, why is it that only you can do it if not technology?"
"Do you have a way of finding places without dangerous beasts to live?"
The scumbags to the Northeast raped these women and killed these peoples' parents. The scumbags to the Southeast killed these other peoples' parents. Is Nelen saying they need to just let them get away with that? Magic to keep them away would be good if it's on offer.
What technology for food and improved-pregnancy will they be able to do themselves? Why can't they do the fastest sorts, and what would they need to pay for them?
"If you decide to join Vanda Nossëo, you'll all get basic income - money that is paid out to you even if you don't do any work - and you'll be able to sign up for classes in any kind of magic that can be learned if it appeals to you. A lot of us live on planets we made from scratch, but maybe if you tell us more about the kinds of beasts I can give more specific advice? Most beasts don't want to live in cities and prefer forests or savannahs or whatever, so if where you're living becomes more like a city then fewer will bother you at home.
"It's really hard to let grievances go. The problem is that - we can bring back the dead. And we don't want to punish people for all eternity. At some point it has to stop. The person who mutilated and eventually beat to death my great-grandfather for refusing her sexual advances served no prison time and now runs a sweetshop in a bus station. We avoid her - that's why I know which bus station, so I can - but we can't pursue it to the ends of the earth. Vanda Nossëo wants to make it so no one feels driven to crimes like that, and that, going forward, no one will expect to get away with them - but not reach into the past and try to figure out what would be just from there. Teams like ours are talking to those tribes right now and they might be getting similar stories about you, and they'll tell your neighbors the same thing."
Fast food and pregnancy solutions include things like "being in a hospital with well-trained doctors who have drugs that require an elaborate engineering and pharmacological base" and "having a demon just make all the food ex nihilo". If anyone is in acute medical distress right now, or, indeed, for the next few weeks, this team can fix them, but the do-it-yourself improvements are going to be things like germ theory and crop rotation.
Three members of the band are pregnant and would appreciate short-term help about it. Food isn't scarce at the moment.
"What is Vanda Nossëo?"
"Why can't you look into the past to figure out what's just?! How do people not expect to get away with crimes in the future if you don't punish any that have happened before?!"
"What can you do to keep the Tesi-Ba and and the Kau-Ba from thinking they can get away with attacking us?"
"The most dangerous beasts around here are the big felids, the big canids, and the hyaenids. How would we make our territory more city-like?"
"What are germ theory and crop rotation?"
The pregnant ones can get Nelen-taps and if they are still having issues he can call for doctory people.
"Vanda Nossëo is where we're from. It's a great big band-of-bands, kind of.
"People can disagree about what's just even if they agree on exactly what happened and who did it. If they attacked you because they were hungry, they'll never be hungry again; if they attacked you because they were hoping to take your territory, they can have some on another world practically for the asking. Whatever their reason was, we'll address it at the same time as we forgive what they've done before. If they attacked here right now and wouldn't stop to talk, I could teleport them away.
"Cities have lots of buildings close together. That means there's nowhere a big animal will want to live, so they'd be going out of their way to go to the city, and that there are lots of people also close together, so they'd be outnumbered every time."
And he can explain germ theory and crop rotation.
"Ah. I suppose the places with lots of people in your pictures are near cities, and Vanda Nosseo live in one? Would you allow us to live with you for just a little while to see whether we like it?"
"If we leave this world, that might mean we stop evolving, right? I don't want to risk that."
Germ theory: makes sense, they will learn from the envoys’ superior understanding of when and how to keep things clean.
Crop rotation: first the envoys will need to convey the concept of horticulture, but after that it makes sense. They'll try planting some of tomorrow's harvest.