Only Brokers can perform certain tasks.

The lease received from the prior landlord states that the tenant did not give a security deposit, her lease is up for renewal in 6 months.

They all had inspections performed (as I think is a requirement here in Texas) The problem with a home inspection is it will not address some major cost items that could be financially stressing for a first time buyer.

I don't think an expense ratio of 30-35% is a bad starting point before securing real financials.

The fixer-upper duplex that I bought has presented many more challenges in learning how to properly fix up and maintain a building but the property is on track to perform very well (around 14% cash on cash).

With regards to the vandalism, I've already thought of using temporary security systems when a unit is vacant in the future (hopefully that puts me on the right track if I'm asked for an explanation). 

Related to that last point and true whether you use one or more QB files, I create a unique category for each note.Because I have ZERO creativity, I use the address of the collateral securing the address as the category.  

I would fill out and send the Security Deposit Disposition letter which would account for you keeping the SD.

As pointed out in other posts, selling securities is a taxable event in taxable accounts.

Remember that ROI and cash flow are only a snapshot in time, an estimate of how a property is likely to perform today.