X-Men Black is a stupid name tbh. Just dub it X-Force.
Anyways, as for the line-up:
Cable- gruff badass team leader
Domino- second-in-command. Brings the squad good luck
Warpath- team bruiser and gentle giant
Boom-Boom and/or
Marrow- all the sass, little stealth capability and a whole lot of fun
Daken- Laura insists he joins 'em. If he's gonna have the whole berserker rage thing going, best make sure it's directed at the bad guys.
Adam X- fast friends with Tabby and/or Marrow. Lots of cursing. Wicked powers that make an impact.
Spiral- spellcasting six-armed swordswoman? I think yes
Doctor Nemesis- resident scientist. Continuously fed up with the antics of Tabby, Adam X & Marrow.
I suggest smaller tactical teams hand-picked for certain missions depending on required powers (Explosives w/ Boom-Boom or stealth w/ Daken & Domino for example). Easy enough to have Deadpool and/or Wolverine drop by for a sales boost.
What do y'all think? Too much?