I don't personally know whether they would hire with less then the required ATP hours and let you finish it with sim time. but i can answer some of the questions you have.

Cuba routes - the last i personally read and heard was they were being flown from FLL EYW RSW. now who gets those flights will be how they man the lines. most likely FLL will be done by FLL based guys, where as EYW and RSW would most likely be a mix of FLL, MCO, TPA lines.

Training - with a ATP it was about 5-6 weeks long and in FLL. They hotel everyone so that shouldn't be a problem for you being in TPA.

Basing - is based off have how senior you are. Most likely you would get IAD before any of the Florida bases. Now having said that me personally and my class when we were doing training we would all end up in IAD but we all got FLL. but they had 220 pilots including my class. its closer to 160 with everyone.

Commuting - IAD from FLL, even with the company paying for the flights sucked because there wasn't really any Direct flights. I don't know anything out of TPA but my guess is it isn't much better.

Reserve - not sure how long till a line, because the lines when i was there were kind of based off how many pilots each base had and how much coverage they had. So how much time on RS will depend on where you go. FLL is the biggest base for Silver per say, with MCO and TPA nowadays almost the same size, IAD is the smallest but most junior of the bases.

When I had bid RS i was flying almost as much as the line guys due to lack of pilots so if you want to fly i don't see you having a problem. Just remember always bid what you want and you never know you could get a line, i mean hell i was thinking they were not going to call me much when i was on RS but i got called a lot, and i knew at least 2 or 3 guys who normally went RS even tho they were high on the list.