Hello Eliana here are the Xiao teams I told you I would test and record for you. Excuse my awful gameplay at times lol ^^;
Timestamps:
0:00 Double Cryo - Xiao, Diona, Anemo MC, Rosaria
1:56 Double Pryo - Xiao, Bennett, Anemo MC, Xiangling
3:35 Freeze? (sorry idk what to call this one lol) - Xiao, Diona, Anemo MC, Xingqiu
5:34 Double Geo - Xiao, Anemo MC, Ningguang, Zhongli
7:29 Builds
Some Notes:
Anemo MC isn't a bad pick as a battery since they can carry favonius sword, and their c6 is pretty good for Xiao. They're good for Xiao teams if you're running a sub dps with him (for VV shred), as demonstrated in the first three teams
Double cryo has the least amount of damage in my opinion, and it's a bit fickle if you're fighting against mobs that move around a lot because 1) Xiao's ult throws mobs everywhere and 2) Rosaria's ult is stationary. It's easy to get all the buffs from anemo traveler though, and the crit rate bonus is always nice
Double pryo has the most damage because XBDIT lol. The team synergizes very well and was probably my favorite one out of all of these! You also don't have to worry about CC because Xiangling's ult follows you and has a crazy amount of AOE
There's no shield for double pyro so you'll have to be better at dodging. Bennett's ult heals for a lot so basically if you don't get oneshot you're good lol
The freeze team is pretty cool (vineboom). You just have to remember to sneak in an auto attack in between each of Xiao's plunges to proc Xingqiu's rain swords, which honestly you should be doing anyways but it could take a bit of getting used to
If you decide to do double geo, Ningguang isn't a bad pick since she can be both a TTDS and Noblesse slave. You'll want more ER on her than mine had though so her ult can be ready once you finish your rotation
There's no healer for double geo, but Zhongli's beefy shield should honestly suffice if you maintain a perma uptime on it. Perhaps shield bot instead of subdps Zhongli would work better
Since there's no sub dps for double geo that needs resistance shred, you can build Anemo MC for more damage. I'd recommend 2 VV + 2 Glad/Shime/Noblesse (whichever has the best substats)
If you end up getting Sucrose or Jean, they are better/more comfortable picks imo. Sucrose is a better battery which means you can lower your ER requirement on Xiao, and she can carry the TTDS, while Jean provides good heals on demand. I still think Anemo MC isn't a bad pick though! Quite underrated imo ;P
Of course, these are all suggestions! Play whatever team you like the best. Feel free to message me if you have any questions :) hope this helped!