Mi3 bought in China..Need to change software

Hi
I just bought a Mi3 in China. Although the language is changed to English, the only keyboard is Baidu and the Google installer does not download without a Mi account.
1) Is it essential to have a Mi account?
2) Can I change the entire software of this phone to an English one?
3) Is it possible to upgrade this to Android 4.4?

Thanks

ppr