So have some questions, Whats the difference between pro forma cap rate and purchase cap rate?

We would not have the time to properly manage our STRs.Not including these costs in your pro forma depicts a misleading result.  

A good foundation would be a combination of the following:Reading through this forum's posts - https://www.biggerpockets.com/forums/70BooksInvest in Debt - Jimmy NapierBooks by Dave Van Horn, Martin Saenz, Gordon Moss, other educators (haven't read them all but they came highly recommended)Scott Carson's videos on YouTube/VimeoPodcastsThe Note Closers ShowNote MBAGood Deeds Note InvestingNote IncYou'll find great tidbits through these resources to help form a working knowledge. 

I look at a pro-forma but I'm not sure how to do the analysis part.

Only people who couldn't form a proper sentence and wanted to know how many people could live in the unit.

Shedrick Archangel You need to build a pro-forma for any purchase.

The plan itself provides you the checkbook control necessary to effectively invest in notes.You could choose to form a LLC under the umbrella of a 401(k) as a means of creating asset segregation, but since notes generate very little in the way of liability, that is probably not necessary.  

Did you do a pro forma?   

What about a situation where one partner comes with all the cash and one partner comes with knowledge side of the deal and they form a partnership.

After that you can just build a pro-forma like any other property and figure out where you end up.