I think that for most characters that we have so far that Superboy would be an acquaintance. He knows them and has gone on missions with them, and he has done his best to teach them what he knows that is worth passing along.
The big ones would be Kid Flash and Nightwing, owing them being the longest acquainted and have spent the most time together. Pending okay from their relative players, this what I have going on:
I think in terms of Kid Flash, Superboy is sad and mourning but he is emotionally stable enough that it does not really bother him - he is in a more mature place by the end of season 2 and is more willing to explore healthy outlets for his emotions, such as therapy with Black Canary, to cope. Obviously he would have liked it if things had turned out another way, but they did not and Superboy accepts that and is moving forward. The world is still there and still needs saving - he will honour Kid Flash's memory and sacrifice by continuing to do everything in his power to protect the Earth and its people.
On the Nightwing front, I am thinking that Superboy would have gotten over being angry about Nightwing's deception. He genuinely believes that Nightwing had good reason for what he did, and when he got in Nightwing's face about it it was a heat of the moment thing. He will have tried to make amends for that and do what he can to bury any hatchets that need burying. Maybe they are not as close as they were back in the day, but by the time of actual play things between them are solid.