If you sell an investment home outside a retirement account you're going to pay capital gains and depreciation recapture if you depreciated. 

No one can ever tell a property owner that they have to have a real estate license to sell what they own. 

We discussed me purchasing the home and had verbally agreed to sell the house to me.

I am considering selling a single-family rental in DC and/or looking for a new commercial loan to purchase the building as much as I (or we if my brother decides t partner with me) can to be a majority owner.

Consider reaching out to 'reverse snowbirds' who may be looking to sell.

Where my head is at and my future goals with REII am very hesitant to sell off cash-flowing properties and have the voice in my head saying "if it ain't broke, don't fix it".

By "partial" I mean renovating the kitchen and bathroom, painting the place, re-tiling the floor and maybe adding some smaller features that can make a difference to prospective buyers, such as new A/C units, new internal doors, or maybe even sell the place furnished (home staging is not really an option here); with no or minimal demolition, and hopefully without electricity or plumbing issues.

They provide passive income if you invest at least $25K with them and they use it to buy, hold, and sell airBnb-able properties.

You could possibly do a bridge loan, maybe a 6-12 month term to pull some of the equity and rehab, then sell or refi if you plan to hold.

Im selling some single families and if I can work things right will hopefully buy a small 12 unit deal due to getting a # from an owner 2 years ago - I talked to him yesterday and he shot me a price -seems fair - he told me he's 80 and has others - I'll be meeting with him in a month or two for coffee and see what happens.