is Fives ship Umbaran starfighter good?

I think 5s is great off the bench where he gives you time to spread some target locks before he comes in and AOEs them all. And as others have said, not having his TM shenanigans at the beginning of the battle can also be helpful. I run Imperial TIE, Vader, Boba for TL, Biggs to buy time with taunt, JV to heal Biggs, then off the bench (in order) 5s, Maul, Ahsoka.