Yes, that's the idea. Silver is the security guard color.

He also has to look magic.

...he can be Very Tall and his robes blowing around as if there were a breeze although there isn't?

Yes, that should do it.

He will accompany them appropriately. 

"Will you be nice if I start by finding my great-uncle," she asks.

"I wouldn't ever be mean to people just because they might be disgusting and I'm not even clear on why they're supposed to be."

"i do not plan to comment, just protect you both."

"Thank you," she says.

Her great uncle is with his family. She looks them up in the phone directory and calls them. "Hello, may I speak to Bar?"

"Who's calling please?"

"Avalor."

"- just a minute."

A delay, then: "Avalor?"

"Hello, Uncle Bar -"

"Are you all right?"

"I'm fine. I have been staying with Elves. I am doing a project and want you to help me."

"...uh -"

"Should we come to you or will you come to us?"

"...what are you doing, Avalor?"

"I have one of the magical aliens along to protect me, it's all right."

"...I'll come find you, where are you?"

She tells him. It will take him a little over a day to pack up and travel there.

They wait! He sings a bit.

Avalor looks a few other people up in the phone directory and calls them and confirms that they are there, for future reference, and writes this down.

"Other people you know who were not blue?"

"And a couple of blues. They didn't kill us all. It was worst in the capitol, people panicked. There are mayors and provincial administrators who really did lose one in three, not more for flinching."

...nod. "Did you know - that was what they were going to do - or -"

"Nobody told me. I think the grownups knew."

"I hate them and I wish the Emperor had tried to invade Valinor so we could tree him."

"You could tree him anyway."

"No I couldn't. People - need to have stable expectations and if we tree someone for invading us that's fine but if we tree them for having been evil before we were even around then all the blues everywhere get scared and if we do it now even moreso. I could but I would be hurting people."

Sigh. "You're right. But he would make such a good tree."

"He would!"

"He didn't like that Voa treated everybody the same about how many kids they could have."

"Oh?"

"I didn't know about this but my politics tutor explained. Amentans want kids, once they spring, very much, and five would be enough for almost everybody to be really happy about it but it's too many if you're stuck on one planet. Two is okay for being stuck on one planet, most people are all right like that if they space them and then they can have grandchildren and that's about good enough. So Voa said everyone could have two. The Empire does things with credentials and awards and blues have to get individual permission from the Emperor and some people get to have a whole lot of kids - the Emperor has thirty-four, he has three wives - and some people don't get to have any and they're trying to do what the Empire wants, so they can maybe have some, instead of whatever they'd want to do if they could have two no matter what."

" - yeah Voa's way is better."

"The Empire says they are making sure the best people have the most children so they will have the best children. But they're controlling everybody and making lots of people they don't think are best miserable. In most places they just do a thing where you have to buy a credit."