1) Although I have read far too many admissions books (credible admissions books!) than I would like to own up to and have met with several hiring attorneys in Miami (from big law firms to businesses), I am in the same exact throws of 0L life as you - applying to law school. So, I would place faarrr more weight on posters who have more experience (i.e. CityLaw, Maintain, etc.)
2) That is fantastic news regarding UMich.! In general, I would pick UMich over FIU/FSU. They also have a nice tuition repayment program. (fyi - we may be classmates come August.)
3) I am born and raised in Miami and lived in LA for several months. LA traffic is by no means comparable to Miami. I mean, if you live really close to work/school in LA, you are okay for the most part. But if not, you are completely screwed. Miami is only miserable for about 1-2 hours out of the day on weekdays. LA is only tolerable for 1-2 hours out of the day on weekends... :/
4) I half agree with CityLaw regarding employment stats. I think the way you use employment stats, like rankings, is what is important. Like CityLaw mentioned, obsessing over which school has 2 or 3% more point in ____ is ridiculous. The point I was trying to make was that, for being 60+ points apart in US News Rankings, the end result (a jobs) is staggeringly similar. In fact, basically all schools outside of the top 20 have basically similar employment stats (for the most part, once you get to the real bottom end it gets fugly). Yes, some schools have more pull in specific regions or sectors than other schools, and that is what you want to focus more on: what region you want to work in and in what legal sector. Can you make an argument that FSU is better for xyz employment stat reason, sure, but only nominally so. The exception, as you mentioned F.D., is with government work. If your goal, as I've mentioned before, is to work for the government in the state capital, FSU is by far the go to school. However, if you just want a private sector law job in Miami, FSU's large government presence 10 hours away is not going to help you in the same way as FIU will. Just the ability to network in Miami for 3 years will help you tremendously...
5) Employment stats to me, then, are not seen in absolute terms (x school has y % in z sector), but rather in relative terms (x school is basically the same as the other 100 schools - or x school is FAARRRRR stronger in every category as y school). This is why posters like CityLaw say ranking isn't as big of a factor as you may think (nor employment stats). For the vast majority of schools, the employment prospects are just about the same. The only real difference is the regional pull and networking ability of a school. The general consensus is if you want to work in a specific city, you go to the school with the most pull in that city. These tend to be schools that are nearby/in the city OR top elite schools (T14 - and even then there are regional biases).
6) All that said, it sounds like your mental state entering FIU, given your other offers, would be a negative one (if not, then at least a not so positive one). This is absolutely the last thing you want. This will lead to self doubt, lack of drive, poor grades, etc. If you feel a strong connection and pull with FSU and a negative one towards FIU, I would go with FSU. This is the enviromental, emotional, psychological part of your decision - and perhaps one of the more imporant ones.
In sum, you will be fine no matter which one you pick. Just have realistic expectations both while in school and after it.
Good luck and congrats!