You need one stable face as you described.I would then take the jointed side and lay it down on the table and do the stable side. The problem with the two remaining sides is that there is no guarantee that you are not making a wedge. I would probably run those two edges through my TS. That would guarantee parallelism and then you could joint them.
For a hold down I would probably put a rabbet on a pusher that would be maybe a 1/2" x 1/2" with a cleat at the back for the pushing part.
Someone I consider a master woodworker once told me that a master woodworker is not someone who never makes mistakes. He is someone who is able to cover them up so that no one can tell.