If that's the case he'd likely need to take legal action to force her to sell.

Maybe some legal types can chime in.

Second, what do should I do before approaching the homeowner to ensure I can legally acquire the property. 

We are looking for a quick legal document to split ownership of the house based on money we put in and time that we are taking to fix it up.

For someone just starting out the Certified Exchange Specialist designation is a nice one to have. 

To me, there is both a legal way to handle it and also a "professional courtesy" way to do so.. 

My question is what the legal requirements are to rent this property to a 4 bedroom voucher tenant.

If you're lucky you may be able to get through permitting in 8 months, but that is not accounting for the time to takes the architect and engineers to do the drawings and design the building, and the city of Denver has a Site Development Plan submittal as well as a permitting submittal.

@Michael Ohman   If you're going to BRRRRR you can still do it with a VA Loan.....But utilize the one that's called a US Department of Veterans Affairs Loan.....It's more designed for BRRRRRs 

Not sure if I could get in trouble by a legal standpoint considering she is not part of the lease agreement.