If you hadn't寫信問了美國國務院(department of state),nobody would have asked you to需要申請豁免. You could 申請綠卡 exactly the same way as your 先生(J2)用IAP66表轉成了H1. No problem at all.
My visa was exactly the same as yours, I didn't write to anybody to ask if I needed waive (because on my visa there are the words "Not subject to the two year residence requirement"), and nobody asked me to waive anything. I have already got 綠卡.