Likely grew his mustache when he was ten. I've met people who start growing their facial hair early af, so very likely.

The big sister thing is a probably but the kicker is Ghazan and ming hua's relationship. that silent, long stare they have and Ming hua's look away seems to be very telling.

the unspoken attraction seems very likely. Ming-Hua's death in a later episode seemed to shake Ghazan.

raised by an older sister to me seems more likely of the other 2.

the mustache he had; not sure if that kind could have started in late childhood.

Mustache and Ming Hua.

Raised by an older sister and secretly attracted to Ming-Hua!

Mustache and Ming Hua

Mustache was confirmed by the creators.

@Hanabi-chan then it’s def Ming Hua’s attraction 😭😭