This is obviously illegal because selling real estate for some on else and receiving a commission is not legal unless are are appropriately licensed broker or agent with a real estate company.

You need at least ten for resale purposes especially if tenant wants a lot of TI.No legal advice given.

@Kenneth C. as soon as legally possible change the lease so they are paying the water bill.

What is it legally zoned as?

My goal is to have every one feel secure in the partnership while also avoiding any unnecessary fees like legal, if possible.

Is it permitted?

Make sure you check with your local laws on what requires permits etc, in my area permits aren't required for roofing unless you have to remove more than 25% of the sheathing.

I didn't realize I needed to get a permit from the town. 

First off, most contractors are not that far behind as far as payments vs work done and they have legal protections to get paid if and when a problem arises via a mechanics lien on the property.

Assignment of contract is legal in most - if not all - states, however, to the best of my knowledge.Hope this helps.