"Paying off" private second with equity in another property

[Doug McLeod]

I'm selling a property on which I have a private second position note securing a loan from a relative.  He wants to keep making money with me and I'd be happy to hang onto the cash for a bit longer.  Besides securing his money with a new lien on a different property, one option I thought about (and he is open to) is to give him an equity position in one of my other properties and become partners.  If I currently own the other property in my own name, what is the best legal and low/no tax option to become joint owners? The mortgage is in my name also, so prefer to minimize risk of due on sale clause being triggered, too.  No problem to pay off the original note first to keep everything clear, but still not sure the best way (or if it makes sense) to add an equity partner after the fact on the other property.

I have an entity I can use if needed, but could I put the property in it as a single member LLC and then "sell" him an equity interest later without triggering major tax or legal issues? Can he simply become a "tenant in common" owner? Implications?

Thanks for any information.  I will confer with my own RE attorney and CPA, but thought some folks out here might have some experience and help me better understand what other questions to ask or options to consider.