What do I need to know before my initial meeting with an IPR lawyer regarding trademarks?

You can best prepare yourself for such a meeting by being able to articulate the uniqueness of the name after doing a comprehensive investigation of its use (or non-use) by others. Google and Lexis are always good places to start such a search. You can also search the USPTO database and your state's trademark database. After you have done all of this, and found that the mark appears to be available, you will waste the minimum amount of time with your attorney.