Looking at your pictures, got me thinking.      First of all, there isn't enough rust to cause the clutch to stick to the flywheel.  Which them led me to think about one other thing.  Which way did you install the clutch disc, because, if you mount it backwards, it won't disengage from the flywheel because of the offset.  Supposedly the side with the springs on needs to be against the flywheel.  IIRC!  I went through my build, cause I thought I had pictures, but I don't.