You might want to consider a joint venture model to start with.

Peter,Have you ever considered partnerships or joint ventures using a Self-Directed IRA? 

Should we open a new joint account, transfer our cash in it and use it to pay for the renos expenses, and later on to collect rent and pay the mortgage?

The property will be Joint Titled, and both partners are on the loanI'm trying to figure out how do we figure out what the fair equity positions for the property are going to be.Does the fact that the property could not have been acquired without Partner 2, account for some sort of equitable value for Partner 2, If so, how do you come up with the value that's doesn't appear to be greedy?

Well done.In my experience, genuine lenders don't come looking for you... you go to them.There are about 1,000 genuine HM lenders nationwide, and they're not hiding.

Thanks to cost segs and bonus depreciation I've gotten 50% write-offs in year 1 - meaning when I invested $50K, I got ~$25K write-off.This was a paper loss even though I received distributions from the cash flow, which means I didn't have to pay taxes on those distributions.People who aren't real estate professionals can only use these write-offs against passive income (like the returns you are getting from the syndication deal itself, or if you are collecting rental income from other properties you personally own you can use it against that too), whereas real estate professionals or those who are married to real estate professionals and file jointly can take the write-offs against their regular income. 

This is a genuine group with quality people who are looking to help eachother.

You could either do a Joint Venture (JV) structure as an active partner. 

From a tax perspective, splitting the properties exactly in a 50/50% partnership might not be possible (unless you want joint owners ship and that will create another partnership).

Some younger investors use a joint venture partner to help supply the down payment.