If I could go back and start over this is what I would do as I did not go to college and learned it all the hard way which took me a lot longer and cost 10 times what a formal education would have cost.

Local governments in two of the NC counties bordering the Great Smoky Mtn National Park have enacted a indefinite moratorium on STR's including motels/hotels and anything under 30 days not directly related to business travel.  

The answer to your question here is going to be based on what the 4% rule is more formally known as: "The Safe Withdrawal Rate" or other similar names including the word "safe." 

Do you have any formal negotiation training?

We (two partners and I) are thinking of doing the same things, and we also have our SOLO401Ks with @Dmitriy Fomichenko.Can anyone chime is as to whether or not an 3 way LLC's 'buy sell agreement' that sets a price at a 'multiple of rental income' (example is 100 x monthly rental income = purchase price.... which happens to be VERY close to the tax assessed value) can be used for valuation purposes instead of a formal appraisal?

There is a property that i'm interested in that is located in Cheltenham PA, literally right on the border of Montogomery and Philadelphia Counties.

I don't know where else in the country you get such asset disparity with a high cash flow city like Baltimore close to a high appreciation city like DC which influences the bordering Maryland suburbs which are Montgomery County and PG county.  

Removed wall between the formal dining and living and walls between the living and kitchen.

I would caution about formal pre-approval until you find a property, but worth finding a good lender who will guide you without pulling credit, which many are happy to do.  

Hopefully, they will accept what they had been told before I agreed to rent to them, and that has now been formalized in the KAPA letter, not to mention in their lease - that they could not add another person to the tenancy.