The contract, option or installment sale, depending on how it is executed may not take anything away and the owner retains all rights.

Are they hard to rent out and retain tenants? 

I have worked out the design so that I can retain a one car garage and still fit a 500 sq ft apartment.

I guess a follow up question to this is: How do I operate between 'my own company' which I want to retain complete ownership for now and this 'new partnership'?

Maintenance of these older facilities is a challenge, so we hired a property management company on a retainer basis.

But by no means would any portion of your deposit be retained for any reason whatsoever.

This way the church retains title and isn't gaining profit.

My humble opinion is that you really need to develop budgeting muscles.  

Leaseholds are a throw back to the British system used by wealthy land owners to retain property rights and control.

I think short term this area will be flat but long term it is growing so I would want to buy them out as soon as possible.Ideally, I would like to retain ownership of all my properties, however, I find myself in a position where I need the money now and it ultimately would be reinvested into a business I want to purchase.