Ok, I’ll bite. 
Modok (Balloon Bomb)
Cap (Shield Slash)
Sent (Drones)
Does your team work well together?
Sort of? Nice combo potential at least, which is what I was going for.
Which assists do you use, and how do they benefit you?
Shield slash is an amazing assist IMO. Great for getting cubes, knocks them towards you instead of away, it isn’t affected by hitstun decay, and it can even be used twice in one combo (granted, pretty situational, but still). It’s my “combo assist”. It also allows for relaunch/throw into launcher midscreen with Sentinel.
Balloon Bomb is there mainly for combos with Cap and Sentinel because it causes unrecoverable knockdown. Extends Cap’s shield slash loop a good bit, and relaunch/throw into launcher with Sent in the corner. Sometimes I hide behind it too, because there’s is no projectile in the game that can stop it once it comes out.
Sent Drones are… drones. I’m sure you know how they work. lol I think Cap basically NEEDS them too, more than any other assist, as they keep the opponent busy for a long time, and the little gaps make Cap’s crossup cartwheel even harder to block. They can also work for Modok to get in, and while not as much as Cap, they can help in combos too (I don’t think they’re affected by hitstun decay either).
Do you have any combos that are assist specific, and would you list the notation?
I have a few vids? YouTube - borawserboxer’s Channel
Why did you pick these characters along with Modok?
I’m a combo-junkie, so honestly, I just wanted an assist that would get me cubes. So I picked Cap. I also liked doing his stupid infinite, until they removed it. :sad:
I had other characters in the last slot to further help Modok, but Cap is so damn shitty, that I had to put Sent in the last slot to help him out. He also lets me occasionally scrub out a few wins with lvl3 xfactor… lol
What team were you playing before you changed to this team?
I had Doom/Haggar in the last slot before, but as much as I love missiles (seriously, sooo good), I don’t really have any fun using Doom, and I don’t like him as an anchor (MY Doom at least). I do think that he goes pretty good with Modok though.
Haggar, I hate using on point. Especially as an anchor. His assist is AMAZING to beat stuff, AMAZING in combos for cubes, and it’s nice that Modok can easily OTG after it, but… yeah, I don’t like using him on point, and I don’t like chasing people with a character that SUCKS SO BAD AT IT.
Case in point, I think Modok can beat Haggar like 9-1 by himself. lol (I also think Modok has an inescapable unblockable against him in the corner when he’s coming in… S-Barrier, whiff c.M into flight, IAD whatever).
How well do you do in a competitive environment with your team?
It does ok? It depends on the opponent really… I also don’t think I’m that great at Marvel anyway to be honest. I never got past training mode in MvC2, and I suck at blocking. I’m an old-school SF player at heart, so these Marvel games really throw me for a loop. I can’t keep track of all the cheap and crazy bullshit flying everywhere… it makes me feel old. 
I also think Cap sucks balls. He’s definitely the weak link in the team. But I don’t care. lol
I was toying with “serious” Modok teams, Mags/Modok/Doom and Mags/Modok/Wesker, and I think they have some good stuff… Also Modok/Morrigan/Phoenix for hilarious runaway… but I just have more fun using Modok/Cap/Sent so I’m using that.