Family Member Interested in Financing next property

Hi all, I've been investing with my wife and we are up to 6 properties. I have a family member with investment cash that wishes to implement in real estate. Being as it is family how would you all structure this deal? I'm able to find properties with a partner I'm working with that secures $400-700 above the mortgage rate.

Multiple questions:

Have them purchase the property that I pick and then help manage with a split of profits?
What would this set up look like?

Or have them transfer the capital to and LLC ($100k-$200k)

Sign an investing agreement with an LLC run by myself to then purchase a property?

What is a fair rate of return and timeframe for a loan of this type?

How would you structure the monthly costs above the mortgage?

I would be finding the deal, finding the tenant, doing any cosmetic fixes.

Trying to find an avenue where everyone wins and also figure out if this wasn't a family member how to structure this deal with a partner. Any help or resources is appreciated.