Put the title as "tenants in common" and create your percentages between both parties (be aware if other party sells their percentage, you'll be joint property owners with a stranger).

The fact that so many strangers with the same passion for REI can come together to help a little guy like myself is just amazing.

Answering the same questions over and over from strangers on the phone is not my idea of fun!

Thank you @Brian Eastman @John Woodrich @Edmund Ricker (and Mat, of course) for chiming in and helping a stranger out here!

What would a typical "dog" do when approached by 4 boys and strangers to us???  

There could be a point where I'm renting 3 bedrooms to 3 strangers in the same house.

https://www.usatoday.com/story/news/nation-now/2017/07/13/homeowner-struggles-kick-out-strangers-her-house/475160001/

I too have considered partnering but there are the obvious pros/cons, for starters perfect strangers in some cases.

My first piece of advice is that you should be asking your girlfriend this question, not a bunch of strangers on the internet.That said, here's how I have structured this in my own life.  

Investors are not consumers.Are you saying child is buying a piece of residential property as an investment, with seller holding the financing, but instead of strangers as tenants, the parents will be the tenants?