My limit is 350 pounds and I could live with 10' to 11' (14' beam). Only need seating for two.
Bimini is a must in FL heat. Heck, I have a bimini on my kayak and love it!
We have a Walker Bay Genesis 310FTD (folding transom, "deluxe") RIB... some kind of plastic, not fiberglass, internal floor, weighs I think 135-lbs bare. Rated for 15-hp.
Our outboard (Suzuki DF-15A, fuel injected, battery start) adds another 107-lbs. At the time, it was about the lightest 15/20-HP available, although I then chose the battery-start model which brought ours up to 107. (And then there's the additional weight of the battery, not huge.)
Walker Bay makes a console version of that dinghy, but I don't remember the weight; info probably on their website. Rated for 20-hp, so the DF-20A could be a choice. I think all that would still be within your weight limit.
(I still consider adding the console to be an option for our RIB; I'd keep the DF-15A and just re-rig for console control.)
Not a recommendation, just factoids for your consideration.
When I was shopping for all that, another options was a bare stainless helm station made by St. Croix at the time. According to WB at the time, that couldn't be fitted to the 310FTD... although that may have really meant they didn't want to undercut sales of their own console. I don't know if St. Croix still makes that helm assembly, but it could be something to look at for other RIBs.
-Chris