I have been considering adding a skill to my arsenal: SALES, to help fund my Real Estate investing.

So with that logic, if two systems are improved and it's more than 2500, combined, would it not qualify under DMSH as you mentioned on your first post, or we can interpret ( more taxpayer-friendly) treatment of applying DMSH to each system first. 

Everything so far has been done through email, the pre-screening, scheduling showings of the property, as well as the application (im using RentPrep) Another thing, with using RentPrep I had the option to have the applicants pay the fee themselves to run the screening (I used this option with all applicants) Im wondering If this still qualifies as the ''landlord'' accepting a screening fee, if not, would I still need to send a denial to the applicants? 

I am not familiar with work you do, but I would recommend looking if you are qualified to invest into Solo 401K.

My point is that each one of them requires a higher level of skill and a higher level of risk. 

Be sure it’s recorded with the city and state and done with a skilled re attorney who -has done these -in your state .

Ask them what you need in order to qualify. 

Are income sources like capital gains excluded from qualifying for a mortgage?

You either need to learn more or have a qualified real estate agent help you.  

Also, it may be a challenge to fill the park with more qualified candidates if it's in a C type of neighborhood.