He is already H1, you can not get H4.
2. 如果我5 月份回中國, 若直接去簽H4, 什麽時間可以去簽? 是隻要我LG的H1B被批準後,還是需要生效後?
It is better that You need to show his pay roll for your H4 , so you need to wait after Oct.
3. 如果是隻要我LG的H1B被批準後就可以去簽H4, 我最早什麽時間可以回美國? 是拿到簽證後就可以還是需等我LG的H1B在10月1號生效後?