He should probably not try to have a lunch conversation. He will return his Pokémon and carry a sandwich up to his room and find useful things to read and vocab to teach the translation software.

He can get plenty of translation work done!

As he works, he receives a text from Frank congratulating him on getting his starters and winning his first battle; apparently after Atyon took over for Kellim as a psychic bridge, Kellim returned to Frank and relayed the events of the battle. Frank also passes along a message from the career counselor sharing her contact info so he can ask questions or arrange future meetings.

Is Kyeo correct in thinking (he texts the counselor) that the first step toward the recommended "first few Gym Badges" thing is to wander around with his Pokémon till they have enough battle experience? How much is enough to try a gym? Should he do this concurrently with or serially with the high school tutoring thing?

Walking the routes and having encounters with wild Pokemon is the traditional way to train up one's team, yes! Getting both his guys to level 15 should be plenty for the first gym. She recommends concurrently; taking some time to study each day will give his Pokemon time to rest.

Should he begin with a tutor - perhaps by video call if he's to be walking around - or some written material?

Tutoring by video call is a great idea! Many trainers do, especially those who pursue the full set of Badges and thus travel far from their cities. The usual approach is to start with written material and schedule tutoring sessions when one encounters a topic they're stumped by—she has recommendations of textbooks and problem sets—but for history and civics, the areas where he has the most catching up to do, she recommends meeting with a tutor first so they can get an idea of how he studied those subjects on his own world and tailor lesson plans accordingly.

Can she refer him to someone?

Yes! For history and civics, one of the high school teachers is available for video call or in-person tutoring in the late afternoons and evenings. For the other subjects, where she judges he's more likely to need only topic-specific tutoring, she has a list of university students to recommend, along with their track records of success at tutoring their subjects.

And is there a curriculum laid out for him or is he just calling these people at near-random.

There's a suggested schedule of topics to cover! It emphasizes that it's not mandatory and is subject to change if Kyeo is struggling with it. It is heavy on history at first because that's the area where he has the most catching up to do, so he'd be calling that teacher first.

Okay. He thinks his voice is as good as it ever is by now, so he may as well see if that person is available now.