Jesus says He never knew them. The context I have been told heavily suggests intimate relationship. Not one of physical intimacy.
So God knowing some and not others in foreknowledge has to do with salvation, because those He never knew He calls evil doers.
So God knowing some and not others in foreknowledge has to do with salvation, because those He never knew He calls evil doers.
You are suggesting His omniscience means He does not know everything is a possibility. Makes no sense.