I know there are services that provide proof of funds but I view that as misrepresentation. 

Finding a good PM will cover your concerns on managing the rental from OOS and a good agent should be able to provide you with their network of deals, including on and off market opportunities. 

My advice without even hesitating, I wouldn't rent anything that doesn't cash flow and provide a good cash-on-cash return out the gate.

This is prime real estate, and is just about the last piece of land in this area.I have begun to develop a commercial property that I own with contractor garages, which is the extent of my experience in this space.I'm trying to get a sense of how to structure something like this, with using LP's, and also partnering with a builder, and carving something out in that regard.Does anyone have recommendations on who is currently working in this space and could provide some insight?

I can provide you with some CPA and lawyer references that support real estate investors.

Paying off the mortgage can provide peace of mind and simplify retirement, while keeping the debt allows you to leverage your funds for higher returns through investments.

Just like professional athletes who still work with coaches to hone their skills, a real estate mentor or coach can provide you with valuable insights, shortcuts, and strategies that can help you avoid mistakes and fast-track your success.

Is her goal to be nice and provide some of the gains or reduce her taxes by trying to split income between her and her ex?

I am a long-term investor, but I also provide services to long-term investors, so my advice is biased toward that option.  

An LLC is potentially one minor factor that might contribute to the evidence that you are running your rental activity as a trade or business, but it's definitely not required that you have an LLC to qualify.