回复：问题棘手，请教大牛们。。。身份还是可能会黑

You had better leave for China as soon as possible to minimize your illegal stay.
Using his H1-B approval notice, his employment verification letter and your marriege certificate to apply your H4 in China.
Less than 6 month gap should be ok to get your H4 from China.
You may also think to approve your H4 from Canada that will be convenient to you.