Unless, of course, the offer is not legally binding.

What recourse do I legally have?

Rentals are permitted.

Otherwise you wouldn’t be writing about it here).From a legal perspective, are there ramifications from NOT kicking them out?

Aside from the immense guilt, you could face major legal problems.

Also, 10 year old renovations will most likely not achieve market rents, which means that any buyer will need to invest in renovating the units)Is the basement unit a "legal" basement unit?

So I have a few questions. 1) As I have never done commercial real estate, am I legally aloud to help them?

Is there a way to do this while legally protecting myself from liability (i.e. having them sign a waiver)?

Hello,Where can I learn about permits, inspections, and regulations for new single-family construction in TX.

If you can keep your cool, and let the courts and the legal system do their job, then you can do it.