1) A brief revue of the Florida Charity Gaming statute (found here: http://www.gambling-law-us.com/Charitable-Gaming/Florida/ ) seems to say that the only charity gaming events allowed are bingo and Raffles. The rules for raffles are pretty strange in that buying a raffle ticket is not allowed, only the "suggestion" of a minimum donation amount. And indeed the prizes must be predetermined and guaranteed.
It would appear that what you have been told is a creative way to turn a poker tournament into a raffle. It might work.
Your request to consult with lawyer is a smart one. My guess is you are not the first one to think of this idea so there is probably already some understanding among Florida law enforcement about this idea, maybe even a lower court opinion or two if Law Enforcement didnt like the idea .... even if you are the first one to try the idea its still best to consult locally.
2) I will respond to your request for referrals privately.
Skallagrim