The YouTube video they sent me seems pretty straight forward so I am certain they are planning on installing the under sink water filter themselves.

Start with calling the planning dept at the city to define the zoning and allowed density 2.

So while this does not give me immediate access, I can have the money back in checking to cover a bill in 2 business days or less, which I have yet to have any unforeseen expense that needs paid faster than that.

Looks like the petrodollar deal just expired and Saudi Arabia has said it does not plan to renew... what are your thoughts on how this will impact real estate?

Local planning department.

You need a relationship with your bank for MHP funding and the big banks aren't interested in your life plan- despite their commercials.

Can I write off any of these rehab expenses on my taxes?

It's likely they aren't including all expenses including property management, taxes, insurance, mortgage payment, and capex/vacancy/repairs holdback. 

There are some other extenuating circumstances that allow one to use more than one FHA loan at a time:- Relocating to an area beyond reasonable commuting distance to your current residence or affordable housing is not available - Leaving a jointly owned property to buy a home, and co-owner (such as divorce) plans to remain in the home.

The game plan is to acquire the land and build a vacation home to become a vacation rental.