"States still may have state income taxes."
Few, if any, states will retain their income taxes. There are a number of reasons, not the least of which is that every state income tax in existence today uses the federal system as its foundation. Without a federal income tax, any state would have to build its own income tax system from the ground up if it wanted to continue to tax income. That would politically and practically a very difficult undertaking.
I am not sure what you mean. I used to live in California, they had their own income state tax forms and tables. Unless you mean the tables are based on the Federal tables?
If so, do you believe that the states would follow the Federal lead and use the sales tax to collect revenues?