We are in the process of something similar. Bought a house as our primary residence with an unfinished basement. Remodeled the main house and living here now. Basement is being built out as a separate 2 bed/1 bath unit that we'll use as an LTR (the city we are in is not a big STR draw). And we were recently approached to rent out the detached garage. Eventually we'll move and rent out the main house too. We also have a travel trailer on our property that we rent out, but not on our property. We deliver it to local campgrounds. There may be local regulations around storing that on your property and someone living in it, so check on that before purchasing. We also lived in the trailer while we remodeled the main house.
I'd recommend starting with a specific market and then understand the zoning, neighborhoods, prices and STR regulations in that area. We chose our city because the housing costs were lower, zoning was more friendly to multi-family and there was more inventory. Then start looking with houses that have expandability: larger lot, garage you could convert or add an ADU. I'm guessing basements aren't common in FL. 😀 You'll soon figure out if those exist and how to look for them. You may find duplexes or triplexes, but those were harder to find in our area.
What you envision is doable, but take one step at a time and focus on a specific city or even neighborhood. We started this journey almost 2 years ago so it can take a long time.
Good luck!