As a medium-term rental, you'd be in better position to be connected with Insurance Company that way.  

Is there a way to remove rent control from these units, especially the vacant ones?

The property definitely needs to be structured in a way to support this strategy, 1 bathroom wont cut it.

Wishing you the best on your success. 

What are some ways I can verify that tenants are protected throughout the entire lease? 

He claims others want to make an offer, but unless it's a full cash buyer (which is rare in our small town), I doubt they’d be able to close faster than us.I’m getting the sense that he may not actually want to sell, and this whole process is just a way for him to tell his wife that no one could buy it.

When looking for a Realtor, here is the best place to look. 

I'm willing to help this person in any way I can.

The leadership part I believe is key, or mentorship is another way to look at it.

It sounds like at the current moment a HELOC would be the way to go as it can help keep costs low by only paying interest on what I pull out rather than doing a refi and being locked in to a higher payment regardless whether or not I find a deal.