Here are a bunch of questions you should be asking:
1. Do you allow traders to trade remotely?
2. Do you require Series 7?
3. What are your commissions rates?
4. What's your payout split?
5. Do you pass back exchange rebate fees?
6. Do you offer advanced order routing mechanisms? Do you have access to midpoint routes and dark pools? Please elaborate
7. Do you have special relationships with floor brokers (floor routes)? If so please describe the fee and rebate structure?
8. Do you have a capital contribution requirement? If not, please describe any risk management parameters (such as max drawdown per day) that you have.
9. Please elaborate on how much buying power you provide? If this depends on capital contribution, please elaborate on that too.
10. How do you process payouts to your traders?
11. What trading platforms are available to traders? Do you charge a platform fee?
12. Please describe any other fees that you require traders to pay?