basement finishing

Hey all,
So my roommate and I (both of us are newbies to this) have undertaken a huge basement finishing project and now we're kind of stuck. We live in Fort Collins, CO and the house was built in the early 90's.

After finishing framing all of the exterior walls we're now on to the interior walls, specifically the bathroom. We know code says we have to build the walls floating. The only problem is that there is a mess of pipes, etc. that run directly in line with the floating wall we need to build which means we don't have any direct access to the floor joist for that wall. In the attached picture our wall will basically need to run exactly where the red and blue pipes are. We know that we're going to have to soffit around the pipes with 2x2's anyways but are soffits sturdy enough to hold the entire weight of a floating wall if that's all that we attach it to? If so, what would an appropriate soffit for this problem need to look like?

Thanks for all your help and information!