We are visiting at the end of October and bringing our double stroller. We wanted to rent a convertible to surprise my six year old who’s pretty much obsessed with them and never ridden in one. Can we fit the double stroller, two suitcases, two kids and two adults in a convertible or are we renting a boring car?
The stroller is a City Mini GT
Might depend on the convertible, but I think you will have a tough time fitting all of this in with the top up and have zero chance of fitting all of it with the top down! We rented a convertible on our honeymoon and our single large suitcase had to go in the backseat whenever the top was down.
I guess it depends on the car, but the few convertibles I’ve been in have had very little trunk space (because the roof has to go somewhere when it folds down). If you find out what kind on convertible you would get, then you could make a better guess about trunk space.
The only other thing I can think of is if you’re staying on-site, then sign up for DME and have your luggage transferred to the hotel that way and maybe you’d find a car with a big enough trunk just to hold the stroller by itself.
You could always rent a stroller once in Disney.
Thanks for the advice, we decided on an SUV instead. Convertible obsessed kid will just have to settle with going to WDW. 
I hope Sci-Fi Drive In is on your ADR list!