Yes on lease and it will help you with your mortgage app, make sure you deposit the rental money and document all transactions well for the bank as proof. 

In regards to collecting rent I would just have them continue sending checks (I imagine this is what they were doing); it really does not take much time to deposit a check compared to the training required to teach a possibly technology illiterate person how to; create accounts, link accounts and pay rent.

So far it seems using deposit at the bank is the best option.

Interest is calculated the same, the only difference is a mortgage uses an amortization schedule to create payments that match a specific term.

The Consumer Price Index soared 0.8% in April to match the biggest monthly increase since 2009, the Commerce Department reports.

She is currently on month to month without any deposit.

So every dollar we deposit is swept directly towards our remaining balance, lowering interest cost and increasing our line available to pull from.

It's really fancy and nice and everything was done top of the line so when it came time to sell it would match the fancy and top of the line neighborhood.TIA!

I agree with @Michael Carbonare:  specify the lease terms and the purchase terms.In one deal I did, we agree upon the purchase price, lease amount, and a nonrefundable deposit towards the purchase. 

@Eric BarriosAlways get an estoppel signed by the prior owner an all tenants regarding lease agreement specifics, security deposit held and amount paid or outstanding.There are countless stories of new owner finding out from tenants after the fact a different stories than what was told by the prior owner before the sale.