I live in the East side of Tucson and since moving here in June of 18, notice that investors buy these houses at a price that doesn’t allow enough $ for a proper rehab.

Properly screening them.

I'm curious as to best practices people might use to evaluate market value properly. 

This may be a good solution for you but be sure to understand the law and operate it properly so you don't lose the protections afforded.Most investors I deal with own the property in their own name.

We will obviously ensure they carry proper insurance, abide by the law, and submit to regular inspections.Question: if they live in the home and operate a business, would you charge them additional rent for the business side?

Hey Fred, something near the beach could certainly bring potentially high nightly rents if properly managed.

I supply my tenant's with a business card sized laminated card with the account number on it.

In order to have a proper comparison you have to take into account the amount of time and effort spent on each investment.

While @Marcia Maynard gives solid advice, WA has a reputation for being super tenant-friendly; whereas my experience in NH is that our courts are less inclined to tell landlords what they can and can't do with their own property, so long as the proper procedures are followed precisely and the landlord adheres fully to all applicable statutes.If the tenants are in a lease term, they can not be evicted for cause not stemming from violation of lease provisions, nor should they be; as they entered into that lease in good faith that they would have a place to live at least until the expiration of the term.

I would suggest turning the water off to the toilets because if the flap needs to be replaced or it does not fall properly when someone stops by to check it can run up an enormous bill real quick.So that the house does not get broken into, maybe add a few light or music  timers and a simpisafe type alarm with monitoring.