Have every detail spelled out, use an escrow account and daily updates verifying all parties are executing their responsibilities.

The owner, the lender or a third party? 

But I just want to start the conversation so we can negotiate the terms so it's beneficial for both parties.

Looking for help and suggestions- I want to say I have learned my lesson and now know to use a third party to hold funds.This is my first time working with a private lender/family member.

It’s a win-win situation for both parties.4o

The Chicago Association of Realtors'® specifically state "When you become a Dual Agent, you owe equal fiduciary duties at that point to both parties in the transaction, and you lose the ability to negotiate for, strategize and advise either one."

This lets both parties separate rather than dragging out the relationship.

The last part is where results happen.

Seems to be there was a bad judgement on the rehab from all parties.

For the lease, can you list the girlfriend as an occupant rather than a co-tenant since she won’t be a financially responsible party?