A solution is to formalize your business arrangement and keep it strictly business.  

To those of you familiar with these types of arrangements, I'd love to hear your opinion since I'm not adept at personal lending.

Well  I always bake my tenants fresh gingerbread Men with a divine peppermint frosting then add little gum drop buttons arranged ever so neatly in a row .

Its best to get you plumbing separated first (including running a new service line from the house to the property line) then arrange with the utility contractor to get the second meter.I would not be surprised if it costs $4-5k when all is said and done, and could be more.

It's a common arrangement in our high-tech world, which allows for specialization....allowing each party do what they do best, in support of each other, and for the common good of serving customers.As an example...

If you put the work in upfront and screen your tenants properly house-hacking can be a phenomenal arrangement.

I called the listing agent to arrange a showing.

Plus, you already found the house and do not need them to spend 4 months arranging to take you around to different places. 

HD arranges for the manufacturer to come in and inspect the dishwasher and then they will make determination of what's to be done. 12/10 - The manufacturer sends their rep.

You, as the new owner, have to provide those same sleeping arrangements.