Good afternoon to you!
I believe that #'s 1 and 2 covered the bases. Your #3 (the correct answer, as you say), that God foreknew that Saul would humble and believe, is really the same as #1. In other words, #3 simply means God was dependent upon Saul...Saul would humble and believe, and thus God saved him. God's saving foreknowledge is still dependent upon what Saul would do.

Grace is not common.