Seriously you're officially launching your sites when there's a lot thing need to be fixed first!
2. How do we verify the bet to make sure it's provably fair? Is there a hash that we can check on the verify sites?
You need to have a good smart contract knowledge to detemine if its really probably fair since the code dictates how they will get a result. You can find there statement below which they replied on my recent inquiry about there reputation. Only a reliable smart contract audit can vouch about there probably fair system.
5. Is there any way to hide my ID and address to be not shown in game history?
There's no way to do this on a decentralized casino because all transaction is recorded on blockchain and also no one knows who you are since you are only providing wallet address which everyone doesn't care to know the owner. You should stick to the Centralized Casino if you didn't want sharing your bet history.