For starters, LLC's are statistically less likely to be audited than standard corporations. 

Offer an LOI.Once the LOI is excepted, then do your due-diligence (walk every unit and audit every lease).

If you go this route and get audited - you risk an agent questioning your deductions.

I'll PM you the name and will now follow your advice on getting 3d parties to audit/oversee.

Don't worry that type of thing is rampant so very low possibility of having any audit issue. 

For example, there are some administrative legal fees I paid early on (notably: Having a lawyer draft up the PSA, and setting up my LLC which holds the title).If I ever get audited, what will the be looking for?

LLC company “safe harbor and/or other contributions” should also come from the LLC so if the IRS audits you it is clear and matches the 5500 tax return and EIN.

Problem solved.Straight-line adjustments are required if your financials statements are audited, as GAAP requires it. 

Just wondering how I could ever prove my parents house was my primary residence in case I was ever audited. 

Or just ask me about the 2 Roth IRA audits I directly handled.