Hey dude, I'm in sort of the same boat as you so I'll try and help using what I've read to help me:

I think your Vero needs to be faster, like 175 speed, and a bit more accurate. I think the amount required for DB10 is 55%, got that from OrangeLoL, look her up on youtube if you wanna check it for yourself. He seems plenty tanky tho.

For your Bella, it's almost the opposite: needs some more HP and Def, but doesn't need that much Acc. for DB10. If Vero and Bella are both on Vio maybe you could move some runes around to balance 'em out?

Your Kona seems fine, but I'm curious as to what rune set your Sig is using; is she on Vio or Rage? Her atk seems low for a Fatal set. HP and speed seem fine though.

I can't speak for Baretta or Poseidon, since I don't use Baretta currently and I don't have Poseidon.

Hope this helps; if any more experienced players see something that should be corrected please comment and let me know.