It's a pretty simple process, especially if you work a 9-5 job for a company (being self-employed like I am meant more paperwork when it came to getting a FHA-loan).With a prequalification letter in-hand a realtor will know you're quite serious about buying and you can begin the process to purchasing your first investment property. 

She asked for a written offer letter, but was manipulated into signing a purchase and sale agreement.

But she want us to get a mortgage denial letter to get the deposit back.

I would personally move forward and not think about it again until someone filed something or sent a letter or reached out.

If it is brick, it may need to be raised/shored, and have a block foundation to restrengthen.

It was an older woman screaming that I must stop sending her letters and stop driving by her house and no her house is not for sale.

A cover letter will not do much for you.

Long story short, some friends of mine were looking to get a group of investors together to purchase a block of one bedroom units in the Houston, TX area for a buy and hold renting situation.

My recommendation would be for the homeowner to send the "roommate" a certified letter advising that the property has been sold and that she must vacate on or before (date). 

I got 3 houses on the same block with 12 combined beds.