the first guy
Kick HIS balls Yeah well gotta hate kids like that. But sadly, assholes will be assholes. My advice would be either:
A) Ignore him and his posturing. When he threatens you, don't pay him any heed, just continue as you were. Or maybe offer him a cold glance. That is, if you are forced to be around him (like in cases when you bumped his chair by accident).
B) Walk away, if you can. Hurts your pride, I know it myself, but sometimes it's for the better.
C) Try to reason with him in a civil way. He threatens you? Tell him you were just trying to be nice. If he really gets to be violent I would even suggest to take a beating, seeing you are on rehab you fighting back might even get you in trouble again, regarding how (un)reasonable your officials are. On the other hand, if it's proven he was the violent one, HE will be in trouble.
D) There's also this "revenge best served cold" thing where you remember/take a photo of his face, get to know where he lives and then
one day shank him in his bed send him a shitcake on his birthday. But don't tell anyone I suggested you that.
Also, take this one with a bit of salt.Whatever you do - just be chill. Showing your emotions by getting angry or depressed could be a sign for him to continue to be a dick to you.
Well, I'm pretty sure you know all this but hey, we here on Bay12 try to help, even if it's just words.
second guy
Wait, is there no way to ignore the guy who isn't even the part of that D&D campaign? I could be misunderstanding things here, but why let him test your patience if he's not even involved? If he keeps asking inane stuff while ignoring the actual explanation you already posted, why, I'd say he's even intentionally fucking with you. I mean, sounds like a kid just so full of himself (getting laid, trying to be a therapist - I mean, srsly). Though I suggest having one final talk with him, explaining just about everything you've told us here. Maybe it's all just misunderstanding and you can work it all out. If not, block him and be done with it. Not worth your time, man.