HEre are the answers to your questions.
1. All cases are federal bankruptcy cases. You would file in Texas, since you have lived there for over 90 days, and have established jurisdiction/venue there.
2. Chapter 7 is the most common, to eliminate unsecured debts. Chapter 13 is used to stop foreclosure, or if your income or assets are too great to file chapter 7.
3. You can show deposit statements as proof of income. You should prepare a profit-loss statement, along with a business income/expense report covering the 6 months leading up to your filing.
4. You should try to get the information if possible. If completely unknown, you can send it to the last known address.
5. You can list the most recent balances, the actual balance on the date of filing will be discharged. as long as you are close, it won't be an issue
6. list both. list the collectors as 'notice
only' with $0 if you have the original creditor listed.