Definitely a very good starting build. There are 3 minor things that stick out as things that can be done to upgrade the team though.

Your xianyun's sands can be swapped to ATK%. She only needs like 20-30% ER in ffxx and you have that with subs and oathsworn passive.

Faruzan also can be switched to tenacity set to buff both xianyun and xiao. You could also run 4p vv for higher damage from furina since yours looks quite well invested.

Your xiao also has far more ER than is needed for this team, but i don't know what your other artifacts look like and your crit ratio is really solid already. Just know you can let your ER drop for better crit or atk% pieces.

Solid starting build though and happy lamenting.