Depending on what status you currently maintain, it may/ may not be viable to apply for H-4. Attorneys will need information on the status at...

If your question is if you can seek change of status, then what you heard is correct - you cannot seek to apply if you have violated your status

You can opt to file if you do not have travel plans. If you have travel plans it can complicate things.

More information on your immigration profile and that of your husband/ children, etc. is required to guide you appropriately.

Filing single or separate applications is a matter of strategy and also needs to be considered depending on the purpose of stay

I-140 filed an d pending is not status. You can repost your question including information on your current status and that of your spouse.

You have not mentioned what your status is in the U.S. Are you are an LPR or USC? If so, you may be able to initiate the process.

The next steps depend on why the H-1B was denied. Have an attorney review and analyze the next steps.

Once you arrived in the U.S., you want to get married? Not recommended. It will trigger preconceived intent issues. Best to have an attorney...

Yes, after marriage you will be able to file based on her country of birth. It is called cross chargeability.