Honestly, it barely scratches the surface of the rehab costs, they need the money more than I do, and I have already factored the rehab into the offer.I'm keeping them month to month and not changing anything about their lease terms, except to get them moved over to MY lease (which is conveniently the BiggerPockets state specific leases we had drawn up by attorneys around the country).

Is this an independent manager or is this person connected to Airbnb in some fashion?

Beyond building code and building permits, if you are disturbing more than 1 acre of land surface for your building and grading, you will need a permit from the Florida DEP.

He has helped my clients in the past house hack in the Orlando area in a similar fashion that you are looking to accomplish. 

Amy,I've not used them with steam heat, but have used them with hydronic (hot water) systems - both the old-fashioned wax-plug/mechanical kind and the newer, electronic types.Many of the newer electronic one allow the the use of a remotely mounted thermostat and some can even be programmed for set-back times (i.e. during the work day or at night).When compared to manual radiator valves, and the humans who will not remember to adjust them, either kind of thermostatic valve will save you energy and money, but the newer electronic ones with remote thermostats/sensors and, optional programability, will save more.

I don't have experience with this one in particular, but I have found facebook groups for stuff like this to be generally overrated - seems super valuable on the surface but doesn't really pan out great 

Cast iron is so easy to clean (if the surface is still good.)

@Steve NafzigerOld fashion market research can go a long way.AirDNA is supposed to be very helpful on this regard as well.

Just an old fashioned clanking steam radiator.

Thanks for the link, that $1400 model that I think you are referring to has a solid wood surface and climate adjusters so that would probably be a great choice.