For how long?
This projects is supposed to die from just start.
The main requirement for this projects to work is absolute independence on well-established money systems, banking systems, financial institutions and government. All of those wants to kill Bitcoin, and have no problem to block your accounts & freez your money whenever they want.
Russion servers or good & expensive lawyers could be solution.
There is no commission at CoinMKT until launch.
I don't think you understand the implications or the risks of working outside of the system. Inevitably, if you are independent of existing money systems, and trade for USD, you WILL have your accounts frozen, lose your customers' money, and be labelled as just another scam. Also, since you said you're not investing any capital, you won't be able to hire any lawyers to protect you.
If you want your exchange to trade fiat, you have to agree to the rules of fiat trading, which means you have to accept regulations. I very much doubt that CoinMKT will have their accounts frozen, as they have gone through all the correct protocols.
Sorry, I know this might sound harsh, but you really need to read up a lot more and understand these regulations before you go starting as massive a project as a new exchange. If you do not understand these regulations, and you do not register with the appropriate organisation, it will all end badly. Please don't put in any major planning or effort until you do, or you will inevitably bankrupt yourself, and receive a class action lawsuit from your customers.
You might be able to get away with a cryptocoin-only exchange (it's still risky though), but without accepting that you need to abide by AML and Fincen regulations you just can't safely trade fiat. Nor will you be able to have even one withdrawal/deposit method, let alone the 20 you want. Don't put yourself through this.
