I'm going to give this a try since I know there isnt too many people on this site. The other engines would work but you would probaly need to change the engine mounts. If your car has the same frame as the chevy equivlant, then you could use mounts off a chevy.
I am sure that Chevrolet and Olds have different transmission bolt patterns. Check this out:
http://tech.oldsgmail.com/trans_bp.php. There are adapters out there somewhere if you want to put a chevy on an oldsmobile. Me, I would try to keep it simple and keep the olds engine with an olds tranny and likewise with the chevy.