I’m local in SA and have midterm rentals here on the NW side

It is important to conduct comprehensive research beyond Zillow; you may want to hire a professional home inspector to evaluate the property's state and repair requirements, as this information will affect your offer.

Also I have some ideas but not sure exactly how I would attack the bigger parts of the curb appeal (not talking about landscaping, I mean things like windows, siding, and support posts)

Look for people that have owned for over 10 years, and get it from them off market even at a deep discount and do the work of fixing it up and renting it for higher, or if you want to buy on market I'd definitely recommend offering below asking, as most multifamily that hits the market in these areas are tremendously over priced. 

You'll want to use your skills and some creativity if you want to push yourself farther into the "profitability" side of the scale over "comfortability".  

:Duplex is listed for 515,000“The 4.25% is a 10/6 arm, conventional loan, Fannie/Freddie product, amortized over 30 years.

To be clear, are you referring to the north side of town - i.e. near Good Sam Hospital; streets like Siebenthaler, Needmore, etc.?

I even offered to have them repaint the house in exchange for a lower rent, but they refused.

I confirmed with customer support that they no longer offer the annual subscription for new properties. 

Along side that with the connections I have already made and my joy for meeting new people growing my portfolio is also on the table.Looking forward to connecting and growing together!