This is making some broad assumptions... you and your family keep your expenses as low as possible while saving and investing as much as possible. 

Now in most cases the same renovation will require an engineer report, and full architectural drawings….I recently had to obtain structural drawings and complete special inspections for a rear trex deck….Just a few examples of costs someone will incur flipping a house in Philly.

That requires more work/resources.

My plan is to live in the duplex for the first year as required by my loan and then rent out.   

That is relatively easy, but ZIP codes are a really poor way of breaking down the city as we have several that cover both expensive and low-income areas.

Whatever rent income/expense we receive/incur, is it split the same % as well?

It's going to be tough, stressful, and expensive. 

The good thing about Texas is that the state does not have a state income tax.The only potential filing oblgation that you can have with Texas is if you have an LLC and therefore required to file a franchise tax obligation.

There was no financing required, since we were assigning the deal to a buyer.

Here's the least expensive one: https://www.redfin.com/AZ/Scottsdale/4620-N-68th-St-85251/un...And here's one fully furnished and turnkey as an STR https://www.redfin.com/AZ/Scottsdale/4620-N-68th-St-85251/un...