@ Drowsy, Zero would actually fit good seeing as how he DHCs well with Doom and Ammy. The only complaint I would have is that he doesn’t provide a good “get off” me type assist. (Doom is prone to getting rushed down) Despite me saying that, it’s not exactly necessary to have one (looks @ clockw0rk) but it is extremely advantageous to have. You’d have to mess with the order on that one though. I’d say Tron would suit him well also, but like Haggar, both of those assists (when by themselves) are pretty much helpless against the majority of the cast.
@ Kensanity, I think Doom and Hulk well together, but not great. I think Hulk benefits the most from characters with OTG assists because they give him combo-ability after an air throw. Wesker fits, though I’m not sure what spot would suit him best. Dante works pretty well too, I’d put him first or 2nd with Ammy by his side. ;p (Dante/Ammy/Doom or Ammy/Dante/Doom)
Taskmaster is another suggestion. HonzoGonzo runs Task/Ammy/Doom and it works pretty well. And I’m sure you could easily put Task as anchor if you want to use Doom on point. So yeah, those are my ideas thus far.