My understanding from a podcast, the reason to get in writing they're leaving is so when I go in after the 12th to prepare for next tenant, they can't raise hell saying I violated contract by entering.  

We entered contractor estimates into the BP property Fix and Flip analysis tool and offered the maximum price indicated in the analysis.

You do not want to enter this business alone and without an education.

And for application fee it all depends on the individual investor what bank they are working with, some investors don't even charge application fees. 

Except that a newbie with a $500k inheritance entering into what is likely the tippy toppy point of the RE market cycle is a dangerous thing.

Also, My state (and lease) allows me to enter with a 48 hour notice to show the property for sale or lease.What is a solution?

However, my lender said that I cannot use an FHA loan because the building is comprised of 4 individually zoned town homes, meaning they can be sold individually.

Ultimately, if you are looking at purchasing more properties I would recommend looking into the Series LLC, as you only have to publicly file the "parent" Series LLC and then you can create an unlimited number of "child" series under it - each offering the liability separation of individual LLCs when operated correctly. 

I want to enter them all but wasn't sure of the best method.  

So I spend only the time it takes to look at my rent roll and enter my expenses for the month into my ledger.