For more info on the tax incentives, read about Act 20 and Act 22.Additionally, the IRS recently designated almost the entire territory of Puerto Rico as an Opportunity Zone. 

The other 75% of the skills required to be a good developer will have to be learned elsewhere (a good mentor is the best way).These include everything from Zoning/Subdivision/Land Issues to Environmental Issues to Permitting Nuances to Design Issues, plus all the differences in financial analysis.

For example, I have a potential client that has decent unit with a solid location but the decor/furnishings remind of a frat boy out of college meets IKEA/Amazon.A unit like this will suffer from poor design and the reviews will show as well which I do not want affecting my reputation or Super Host status.Do I just decline taking them on if they are not willing to work on it?

For me, this statement is key, "The owner designated you as agent for the purpose (among others) of finding a tenant.

What is a good starting place for an estimate to completely overhaul the interior of each 900 sq ft 3br/1ba unit as current tenants move out? 

I have a good network of service providers for work, design, questions about permits in the local market, etc. if you want to connect.

I added extended driveway, RV parking, back yard landscaping w/ covered patio, shiplap on two interior walls, and painted accent walls in every room.

Happy to connect, I'm with a design & architecture firm in Florida.

“Maybe [Meta] should have had a policy against any sort of promotions like that,” says Jeff Smith, a former Facebook product designer who says he lost more than $50,000.

@Alan Asriants, my wife, who is a designer, and her other design focused friends, refer to these as "Dude Flips".