Evicting them, even after purchase, could be a lengthy and costly legal process.

So far the process is simple. 

Everything you describe though is just the normal process of how taxes are reassessed when a property is sold.  

The process has been difficult and stressful and we almost gave up a few times. 

She's been stuck with the city process and wanted some advice about how to get her plans approved.

I know this is above and beyond what most municipalities require, but being fair will make the whole process easier.Additionally, a new landlord can reduce the 60-90-day notice by offering more moving assistance (cash and/or labor) if they move sooner rather than later.

This would be an easy decision however I do not think you can come close even with you being active in the process.  

Renovating a 3-unit townhouse sounds like a great project.How’s the process going so far? 

Each state might have different process.  

The best strategy I seem to have deployed so far was to contact all my current tenants and let them know I’d give them a cash referral fee of $250 for anyone they recommend to me that goes through the vetting process and successfully moves in.