Do you agree, or not, that forgiveness of sins is required for salvation?
Again, I'm not preaching against baptism, and if someone claimed to be saved by faith but refused to be immersed I'd have my doubts. But one shouldn't put the cart either in front of or beside the horse. The Bible is clear that faith results in salvation which results in baptism, not that faith plus baptism results in salvation.
Again, look to the thief on the cross, who did nothing save to put his trust in Jesus hanging next to him. To try to parse that down according to "which" covenant was in effect is to miss the point--in all covenants, righteousness is only obtained by trusting in God (Gen. 15, Rom. 4).