The only thing that would make this bad is if the vacant unit were rented and not leaving.

They will likely also need to close any access points to satisfy city inspectors that the now capped chimney cannot be used to "vent" anything in the future.You will likely want a demo team that is much cheaper to do the actual demo and haul off, but you need either the mason or an engineer to stipulate how far down they can/should demo, while leaving enough room for the cap to be effective and maintain any structural rigidity into the future to not create more issues.Long story longer, I would call more licensed, insured contractors.  

Incentivism them to get out of the house--we have offered full deposit return (obviously that is done day they leave--draw it up if you need to so they are comfortable). 

Now these 5 year, 7 year, and 10 year terms will mature leaving lots of owners unable to refi or break even. 

That way since there is a connection to the basement there is not issue with you crashing down there.If you don't want to do something like that, I would cut the basement off from the first floor and just rent the first floor, leaving you the basement to crash in when you want.Or see about getting the basement made into it's own separate unit now that ADU are allowed in Mass (although the law may not kick in until the new year)Also your town may now require a certificate of occupancy to be issued before you can rent it out and they may have something to say about this basement connection anyway.Just my two cents as they say.

Eventually we just decided on remodeling the bathroom where the original pipe damage was and leaving everything else be. 

You'll also be leaving liquidity available should a great deal come your way instead of being locked into just one project at a time.

How did I leave out Profit?

One way to solve their burden was to write off the properties and leave them in the owner's name.

I am Texas based so may answers will skew more towards my region but I would leave to hear what are some other areas you may be paying attention to that isn't as popular as some of the main stays (Smokies, Joshua Tree, etc)Mine right now are 1.