Cape Coral through North Port have similar market clients. The Cape has a pretty neat down town area, Fort Myers tends to be where most of the big companies are. Punta Gorda has few spots left to build that is close to anything but great history. The downtown PG area has a lot of great places. Developers are starting to move Port Charlotte and North Port because there is land to build on. Also it's about 30-40 mins away from the beach.
Out of all those places listed I would focus you build to rent on Cape Coral, Port Charlotte, or North Port.
I work with developers and investors and the main problem is the shortage of available houses. There are currently 455 SFR on the market in Charlotte County while 1100 pending offers (180 days). 2607 vacant lots for sale and 1469 pending (180 days). Houses are moving real quick, as in we list a house and it's gone with 24 hours, so vacant land and new build is what everyone is moving to.