Need some advice for a unique situation

One of the most important ingredients is D-180 syrup. The people who make the syrup do a pretty good job of making clone recipes.

http://www.candisyrup.com/uploads/6/0/3/5/6035776/rochefort_8_clone_-_040.pdf

http://www.candisyrup.com/recipes.html

 

Unless you will be using your friends equipment I would at the very least suggest doing a batch with your friend that you'll both enjoy for the short term first to see if investing in the equipment is even in your interest. Kits aren't too expensive, but they do take up space if you don't have the proper storage. Just throwing that out there as you don't sound like you're really investing in a hobby as much as a single batch to hold onto for a while.

Seems to me like you really should just brew a batch with your friend and buy all the ingredients and see how it turns out instead of waiting a year or so to find out if it's even drinkable.