I looked into paynear me and they are not accepting any small businesses at this time.

You shouldn't accept partial payments.

A conversation with the underwriter would be my next step to see what they would accept

With any of this, I'd talk to some local area investors and get a good agent behind you that can help with these things and advise you of the pros and cons of each.In some areas, I've heard of writing letters to the sellers, or even giving a acceptance type gift (like for real, other agents have told me in big markets that they will give the seller a non-refundable $25k upfront to accept (even if there's like an inspection issue or something!

Even if you get lucky with long term tenants who accept regular rent increases, you can't count on that when running the numbers.

Would it be considered acceptable or ridiculous to ask an accredited and very active RE investor who is interested in a deal you are looking at (whom you hope to develop a positive relationship with and or/ partner or invest with you) to sign a non-circumvention agreement, prior to them seeing the deal AND prior to having the deal in question under contract? 

There would be common kitchen/eating area, a couple full size bathrooms, and a larger social space, These are examples of creative value adds but not ones appropriate for you. 

The scariest part of the house was I did not have all the cash available, I hustled my A** off to have the cash in the 30 days after my offer was accepted.

Mailers, billboards, social media, referrals , door knocking, sheriff sales etc. 

It took me a year and a half before I even got an offer accepted on a property.