Any phrases such as "finished basement or attic", "in-law suite/arrangement", "seller nor listing agent can confirm the legality of the basement/attic unit" are a few common ones.

Our current lease, based on a template, prohibits subletting, so I’m not fully aware of the pros and cons of this arrangement.

And, I sure as hell won't agree to any arrangement whereby I owe someone my time on a prolonged basis. 

Similarly, some leases have options to purchase or lease to own arrangements.

Timeframe, legal considerations, and best practices going forward of course vary by jurisdiction.You can't count on believing that the family member doesn't already have utilities under their name or similar arrangement that will keep the power on for them.

However, are there tax implications to this kind of arrangement? 

It's also nice to include some photos if you want things staged, or the coffee table items arranged a certain way.

Need the ear of power, it can probably be arranged.  

How do you think about this financing arrangement in terms of determining equity? 

I have found that if you can arrange spots correctly (one on each side and two in the middle) you can fit about 60 spots/ acre.