In context, in Eph 2 Paul is contrasting being save by grace and being saved via the Mosaic Law. The other issue is a straw man. If God sets conditions for salvation then one must meet those conditions. It has no bearing on God or what Christ has done. One either meets the conditions or they don't.
Here's where the argument falls apart. Are the lost saved? I suspect you'll say no they are not. Now, I could ask all of the same questions that you asked above. The difference between the saved and the lost is that the saved have believed, thus they have met a condition. However, the saved have not yet been saved, that comes at the resurrection. The saved have been betrothed to Christ, they are not yet married.
2 For I am jealous for you with godly jealousy. For I have betrothed you to one husband, that I may present you as a chaste virgin to Christ. (2Co 11:2 NKJ)
Paul uses the analogy of marriage. What happened to a betrothed Jewish virgin if she was found to be unfaithful?
23 If a damsel that is a virgin be betrothed unto an husband, and a man find her in the city, and lie with her;
24 Then ye shall bring them both out unto the gate of that city, and ye shall stone them with stones that they die; the damsel, because she cried not, being in the city; and the man, because he hath humbled his neighbour's wife: so thou shalt put away evil from among you. (Deu 22:23-24 KJV)