I recommend that you look at Notice of Defaults, Vacants, Tax Liens or Probate. 

I would also give her x amount of days to move but let her know you will have to charge a prorated fee per day after that to move for occupying both units. 

Dig deep into tax strategy, tax efficiency, etc  Learn about estate planning. 

Am I setting myself up for a tax nightmare?

From tax stand point I would think you can separate from primary and be okay with IRS being that IRS will not be local code enforcement.  

@Deirdre Lizio see a lot of competiting PMCs start with a pledge of doing it better than "what's out there".Always interesting to revisit them 3-5 years later - after they've experienced the reality of challenging tenants AND owners.Look no further than Evernest: they started out with flat fee management at $99/month and promises of better & fairer service & pricing.Now they're at 10%, capped at $199/month - wonder what changed?

Texas is very landlord-friendly and also does not have income taxes. 

It's going to offer Strong economic growth, Appreciation (especially in DFW), Tax advantages (no state income tax), and a Growing population, including infrastructure and amenities. 

She came back to me and asked if I would pay her 50% of my cleaning fee if guests cancel within 48 hours.

Quote from @Samuel Hudson: Hello friends I am new the market and recently bought a home in Weehawken 6 months backs .Its a three family home and we are currently doing renovations Right now.The rent leveling board told me that two units would have to follow a rent of 1650 for unit 1 which has three bedrooms and another unknown amount for unit 2 which they don’t have the information for .The previous seller I purchased the property from bought it as a tax lien .He has kept the property vacant for two years with no tenants before selling it to me .However ,the previous Owner he bought it from must have had tenants .I am putting in a lot of money into renovations and want some clarity on the situation I am in .The property has been vacant for the two years and currently still is as we are doing renovation .It would be really appreciated if anyone can assist me on what information needs to be provided by from the previous seller for me to be able to set the rent based on the market value .Thank you .