Currently, I work as a Technical Support Representative Lead for a large cable company that operates in the New York Metropolitan Area.

I assume she still technically owns and can sell the house since she has not signed over the deed yet nor has the auction been completed?

of the platforms in the industry have very basic underwriting and aren't really staffed or equipped to do their diligence well.  

When should you technically start advertising for an available rental?

Just read the title and technical description, you should be able to identify/find the markers.

My intent is/was to keep it simple on technical information (key points) or more to residential product leave.

Technically, if you change ownership from you personally to an LLC the bank could call the loan due at which point you would have to pay it all off. 

Although technically correct regarding the due on sale clause, I've never seen (or heard of) a bank actually calling a loan because title was transferred from personal name to personal LLC for the purposes of asset protection.Regarding seller-financing, the downsides can be a higher interest rate, shorter term, not holding the deed, and more practically, finding the deal in the first place. 

A-paper commercial banks are still in the 3.75% - 4.25% range right now, so technically 5% is better than that.

There are a lot of people who are over leveraged, so they can technically afford it, but it's not a comfortable position to be in.You may want to consider how much you're comfortable paying per month and then working backwards to see how much that works out to be in the way of a mortgage (and if there is anything worth it - however you may want to qualify that) in your range.