There are benefits to going both directions.

I would say condo investing is in my opinion the way to go.

"If they would just be quiet we wouldn't have to go through all this."

Is rezoning a three unit to a four unit something I can reasonably pursue, and if so any tips on how to go about doing so?

Not knowing what the net yield is you may have to partner with others for a deal or two the generate enough capital to go off on your own.

It seems if you build it out into a proper modern small set of apartments, you can avoid any big maintenance issues for a long time, as well as making something highly desirable/and therefore priced accordingly. 

I think if people have the money and desire that might be a good fit for some.

I searched hubzu in the search bar, but there was too much to go through.

I once had the same issue with a rodent that died in the attic, and I called multiple pest control companies and they all told me the same thing - that all they could do was charge me to go up there and look for it in hopes of finding/removing it.

I am in Pasadena area so willing to go 1hr away east west, The closer the better. no adding sq ft at this point.