James loves Tony and he will do his best not to take any resentment over secret-keeping and how they grew up out on this version! He'll be a little weirded out about there being all these different timelines and stuff and I think he's still just going to look at Tony as just Tony, albeit obviously a bit younger. But he's family, 100%.
Torunn is his sister and he loves her. He's a bit protective of her and the others, but he does more or less see Torunn as an equal, too. I'm taking him from the end of the movie and I couldn't find anything that explicitly said how old they were at that point, so I am just going to say he is 16 because the one reference I found said that was the right age LOL.
He will be friendlyish to Lyra and Cassie, too. Friends for James, anyway, because you know he is kind of a broody little shit.