Suggest emailing them instead. I’ve always gotten responses in pretty good English, and surprisingly fast too (even when emailing them at weird times outside working hours).
You can update it on Shopee, it’s a bit annoying though and you need to contact customer service. If you have money in your Shopee Wallet, you should withdraw that before you update your bank accounts (this was the biggest problem for me). You don’t need to create new accounts.
Chinese and English both fine.
Err…kind of. You can use an English name on Shopee for the ID verification but can’t link that to an EZWay profile with an English name. I have a thread complaining about this issue: