Still, I'm concerned about potential tax complications given the property's location in Maui, my residence in California, and my in-laws living in Washington.Am I overlooking anything crucial here?

What subject to invokes is entrepreneurial risk; the thing all real estate investors live with in an attempt to grow our assets, and gain a financial “free” lifestyle.  

I have documentation of payments and evidence he lives here and a rental agreement.

NY isn't TN so you need to do your research and check the comps.If you acquire it, you'd have an option to flip it, develop it or live on it.  

I'm currently living in Boston, but plan on moving back to the Pittsburgh area in the next month.

While your immediate position doesn't change, you now own a property with 200k of currently inaccessible equity.Also with your first one, if you can put down 5% or equally low, occupy it, and do a live-in flip, you may not have to refi; save up for another 5%, do it again, new primary loan, etc. 

However I only have one tenant living there and he doesn’t use much bandwidth and neither do we on our side.

I'm a former CA resident now in I live in Lake Tahoe and work in the Reno, NV market.

You can Rent a Big House to live in and just rent Rooms if you can stand to live with other people.

One we rent out, the other we live in.