well sombra iw ould say doesnt matter much, unless theres a Zen then sombra ult first so he cant counter, dva i would say try to do it at the same time or zarya first if dva goes first they will scatter
It differs for me as a Sombra main. If there's a D.Va on their side, I would ult first and then let Zarya ult cause I've seen far too many D.Vas being fed by accident. Other than that, Zarya first.
Zarya first on most combos. If they hear the other shout, they'll scatter, making it harder for graviton to work effectively. Sombra could do it before, to stop things like Orisa's fortify from allowing her to escape.
Problem is it's about communication if you shoot ult first and they take too long to update your ult was wasted as for dva when I hear "nurf this" as zarya that's when I ult stopping them from trying to scatter but if you both have mics call it and you both should hit your ults at the same time as for sombra if zenny is there have her ult first but make sure you ult immediately after