HITBTC is shady exchanges and have fake volume trading, there's no reason why someone need to use this exchange.
I have no idea about HITBTC as probably I have never used this exchange site. If I have done any, I cant remember that yet.
The problem is with HitBTC. They specifically do not allow you to pass the KYC in order to prevent the withdrawal of money.
I am not sure either they are legit or scammer. But I have a suggestion which you may follow. For your passport ( do not scan your passport), just take a image/picture of your passport by your mobile. And for selfie or other matter please use your mobile phone's camera. I think it may help you.