I don't think buffs/debuffs extend past a single team, so I can't see how team order matters much. Character order matters slightly on normal nodes because you can minimize wasted overkill by putting the aoe/multi attacks first and single/random (Anemone/Kale/etc) last. Probably not relevant for bosses though.
For the upcoming event, from what I've heard, unless your team is dying before turns are up, debuffs aren't as useful so stacking them is of limited benefit. As many girls with + Raid boss attacks as you can combined with other strong single attacks to get the most out of them. That gave me a nice boost in the Adonis RB event (first team was Cyrtanthus+ rainbows with strong single attacks - Fl.Peach, Mei, Alpinia). But for this event, I don't really know for sure.