One we just took on under management required a $175 admin fee to register the condo as a rental with the HOA. 

If you're difficult to deal with or require extra handling (i.e. pays each month's rent in 2 or 3 payments) there's a $250 upcharge on what the rent increase would be normally.

My wife and I would like to buy a rental next year (most likely using a DSCR loan, to dodge the DTI requirement), but I'm not completely sure if that would get us stuck down the road.

I like option #2 but you might not be able to buy too many homes with just $75,000.You might be able to get into some decent properties in the $200,000 range in those cities which would require 20% down which is $40,000.If you had $25,000 ontop of the $75,000 HELOC, you might be afford the downpayment, closing costs and a small rehab budget.Best of luck!

The size of the data sample required for accuracy is definitely key. 

I don't want to change our software for accounting / management because I have another LLC that requires quickbooks. 

From my perspective a 6% commission has never been required.

However, it is important to familiarize yourself with the legal eviction process in your area and follow all required steps to ensure a smooth eviction process.

One of the brokers said he could send me dealflow but required that I sign a non exclusive representation agreement.

Texas law concerning series LLC specifies that separate records and bank accounts are NOT required for each series for the separation of each series liability to be recognized in court.