Fun team

Very strong AoE, good in single target, Kokomi brings the extra hydro app Xiangling wants (AoE app too), she brings team-wide healing for Furina, she brings the Hydro Resonance that buffs both her damage and Furina's, she brings hydro particle generation for Furina, lowering her ER reqs, and Kokomi even benefits from Bennett's buff since she does benefit from ATK. Works great.

The only small downside of this team is that since you spend a lot of time on-fielding Kokomi, funneling energy onto Xiangling becomes a bit more complicated, making Xiangling's ER requirements a bit higher than regular National variants. But even then, I was still able to run an ATK% sands on Xiangling, as she already had 200% ER. (although an ER sands would trade some of her damage for a more fluid rotation, which isn't necessarily such a bad thing, especially if your ER is under 200% with an ATK% sands)

[Music used]
Genshin OST - Serene and Fathomless (Ayato's Theme)
Genshin OST - Good Night, Liyue