If not, I believe you simply have to give them Proper notice of the sale.....in either case they have the right of redemption for 120 days, then their lien becomes invalid.  

I would stipulate that they are FULLY moved out and also cleaned up properly before you hand the cash over.

They will have to find a renter within 2 mos, which is easy. 

I fully accept this if there is nothing I can do because I didn’t take the proper action to protect myself, but I hate letting a contractor get away with something like this. 

I do not know about cheaper, but i believe it may run the same or a little less, depends on how much wall / ceiling needs to be opened and patched to block off the ducts. the 1st floor should be easy to re route to the new unit, so essentially you would be blocking the feed and return to the 3rd floor. the only " new" duct work ( if you can not tap into the old ducts on the 3rd floor) is the new ducts for the 3rd floor. so you would have 2 new units( or 3 if you want to replace the old one) re routing 1st floor feed and return, blocking 3rd floor feed and return and new unit and possibly duct work in the attic. you will get a better system then using multiple mini splits per unit.

I like Bagley as an area, but not easy to get property in there nowCheersLindsay

I am in the process of acquiring a piece of land in Chicago (proper) and became aware that I might be able to build a billboard on it.

She keeps rent just below market so finding good tenants and keeping them are easy so everyone is happy.

If I’m getting expensive money I want it to be easy.

They don't call it investing because it's easy.