Recently, bunch of properties are having plumbing issues and even very expensive furnace issues.

Maybe time for a new platform to emerge out of this and Airbnb regulates themselves into retirement.  

been in and out of alot of houses and buildings over the years and sure it can be creepy being alone in a old basement on a old farm but have never seen anything besides plumbing nightmares. 

The mortgage will only cover an additional 10k for repair due to the fact that I can do installation of electrical, plumbing, tiling, framing, hardwood flooring and landscaping by myself.

More than one person has said that to be successful, copy what other successful people do.Given that you are just starting out, I can't emphasize enough that you need to learn the real estate business (and it is a business) as well as the local market before you spend any money on buying property.I will (partly) answer one of your questions: Overall, Maryland is not, in general, a business friendly state, but each jurisdiction has its own rules and regulations.

I know there is regulations in regards to being dual licensed especially when it comes to FHA.

Silicon Valley championed the concept of turning America into a land of entrepreneurs taking advantage of flexible hours, unimpeded by regulations or specialized training.

We lofted the ceilings and rebuilt the deck, new roof, skylights, electrical, plumbing, kitchens, baths.

All new plumbing fixtures; replacing wood on deck and repainting exterior (trim).

Depending on how easily you can get to the plumbing you many need one at each fixture.