All the non OE parts are just "adding to the soup" like Clavurion says
If the aftermarket IAC motor made things worse then it would be a good idea to replace it with a new OE one, maybe part of the problem, maybe not the problem at all but a reasonable thing to try. And yes check for vacuum leaks and "passing" a smoke test doesn't mean there is no leak. If you posted this multiple times on multiple forums with different information it's adding to the soup as well.
Are you using a diagnostic platform that is going to get all the codes ??