回複:TN 還是 H1 ? 請大家指教, 多謝 !
Sounds like you will have more headache with J1 waiver. You must either get a waiver from China or go back to China for 2 years(?). The time you stayed in Canada doesn't count.
SSN should be the same. And it is linked to your J1. SSN application form requires you disclose your previous SSN anyway.