Though there are some creative solutions to this and other issues - Fellow BP member  @Dave Foster is the man to talk to about the 1031 side of things, and he has a lot of tools at his disposal to help with all of the above. 

You can always dispose or sell the older unit.  

He’s done laminent flooring, I pulled up the carpet and pad and disposed of it to assist in my costs and have it ready for him to jump in.

Have them collect anything they wish to keep, and get in writing permission for you to dispose (or do whatever) with anything they leave in the house after signing the agreement.

1 - Any qualified charitable organization that aligns with his values, and accepts donations of real estate.2 - If he donates the land to a qualified organization he wouldn't realize gain or loss on disposal, instead he'd get a charitable contribution deduction for the fair market value of the land. 

That will dramatically change what financing abilities you have at your disposal. 

So I decided to cut down that tree and dispose of it.

I bought 3 cheap and unloved homes during the 2008-2016 economic problem, but now that that problem had been disposed and good times have returned I'm stuck!

You could record an option if seller chose to wait to dispose after tenant moves to kill your competition.I can't answer your sub2 question without know all about debt. 

I can't believe people would just dispose of them in the walls like that.