Any character could work to an extent, but the most common answers would be:
1. Big Band or Cerebella, in the order Peacock/Squigly/Big Band (or Cerebella)
2. Peacock: George's Day Out, Squigly: Drag n Bite, Big Band: Brass Knuckle (H), Cerebella: Lock n Load (H).
As an alternative, you could use Beat Extend (L or M) for Big Band if you want better anti-air coverage and up-close Squigly pressure at the cost of losing a long-range assist for Peacock, and using Cerecopter for Cerebella gives you the same tradeoffs, with the added downside of losing an invincible/armored 'get off me' assist. There are other non-standard assist options that could work for your team like Big Band's Giant Step (H), Cerebella's Battle Butt or Squigly's Center Stage, but if you want something standard and proven you're better off with the options I listed above.
edit: The more I think about it the more I think Battle Butt assist might be surprisingly good for your team if you end up choosing Cerebella instead of Big Band, because maybe Squigly can use silver chord or center stage to combo after it hits. But I'll leave that to the people who know how to play Squigly. Either way, Big Band has the best assists for your team so ignore this part if you'd rather play him than Cerebella.