An older building with poor insulation and a lot of air leaks will be challenging with a mini-split.

I'm sure these are low-income tenants who aren't suddenly going to be able to pull another $300/month out of thin air. 

I’m a U.S Air Force combat Vet and an investor and licensed Realtor here in DFW.

My father bought a 1964 Barracuda that we intended on restoring, but instead I had a S-10 that I put a bunch of money into (air ride, wheels, etc.)

One of my investor clients bought a large ski house and rents it constantly on Air BNB, she may be open to chatting with you about her experience with that business model and she lives just north of Boston.....hers sleeps ten though, so  a different property than what you're considering.

I’ve done that a few times and it’s worked out much better/cleaner for all three parties 

The sellers recently installed new forced air heat in all the units and the electrical service has been upgraded.

Not sure what your budget is but I would get a property that you can Air bnb.

Anyone interested in splitting the costs of a VA for Air BNB?

If it is under the house the structure engineers wearing white shirts and ties who worked in the air conditioned office aren't interested crawled under the house.