I know I got to this post late but I thought I'd respond for future refrence. There are 3 Shia Mosques in the Orlando area as mentioned:
HIC, Husseini Islamic Center, Sanford FL (this is the one I go to)
Biggest Florida Shia Mosque, Ashura Occupancy reaches about 900 people, majority Khoja, English Lectures, and somtimes 25 mins or so Urdu lecture after English
JIC, Jaffaria Islamic Center, Kissimmee FL
Medium size, mostly Pakistani as far as I know, not sure of lecture language
IEC, Islamic Education Center, Orlando FL
Smaller, diverse, decent amount of arabs, I've been there once to give a presentation and I remember some guys talking about how they were from lebenon and the maatam was in farsi and a few notice boards were written in Arabic so I think its more Arabs there. Very nice community and show great hospitality.