Co-Owner/Co-Borrower relative title/vesting question.. rev trust?

[Jay G.]

- Myself and a family member (uncle) are purchasing a property.  

- Uncle is Non-Occupying Co-Borrower.

- My family and I will be living in the property as our primary residence. Uncle has own primary residence elsewhere.

- Uncle putting 100% of (20%) down payment + some initial renovation costs down during purchase via conventional 30yr loan.   I will be making all payments, insurance, upkeep, etc. from there.  

- We will each have a 50% interest in the property. 

- Our intent is to refinance Uncle off of title in a couple of years.

Uncle has a revocable trust where most assets are kept. I guess I'm a beneficiary to 95% of that trust.

Anyone see any issues with having title vested as  myself as individual + name of uncles trust?  

Where/how does percentage ownership get recorded? On a separate agreement between us? 

Also I would like to give him protection against the initial cash outlay which becomes instant-equity in the home (i.e. the down payment + renovations).  Example of that totaled $100k, then I would want to give him/his trust 50% of the gains or losses after that $100k was given back first.  But maybe that's not the best way. 

We just don't want it to be considered a "gift" - because it's not. Intent is short-to-mid term investment for him, and getting into new primary residence for us (where we otherwise couldn't w/mortgage at this time).  Uncle of course is free to do whatever he wants with his "share" of property.