If you want to start building a portfolio in Austin and have a long term strategy then house hacking a duplex or even picking up a SFH every 1-2 years could have solid returns, given historical data.  

Or please advise me on how to enter my data into the system to give me an accurate analysis.

With either one just be completely honest with the seller that you will potentially be brining in a partner and/or assigning the property to ensure you have the most efficient process so you can get this deal done. 1.

I created a big spreadsheet, and find lending data goes stale every few months as rates and terms change. 

For STRs... what's the best way to gather the data on utilities, pest control, pool cleaning, general maintenance, etc...?

Good list @Jill F. and great call on estoppels--very important (this is to ensure that the rent roll and security are accurate).

Terry Burger a close friend and associate of mine is a self-proclaimed data geek and his super power is understanding the retail consumer and how to find opportunities in current data trends.

Baylee,Reach out to me via email and i will get you started and ensure you understand your options. 

@Monica Ponton Ensure you have a due diligence contingency in there to give you time to walk and inspect the property.

Both were/are live in flips that get reappraised around October once the flips are done and the market has received all the data it needs to value them.