Duplicate question has been addressed on this platform.

CRB at the embassy/consulate is one requirement among others. Consult with a lawyer for a comprehensive guidance.

H1B cap employer is eligible to transfer to another H1B employer.

No, your passport is not going to be an issue.

There may be other options for your consideration. Consult a lawyer for further guidance.

The sponsored employee is required to work for the sponsoring employer upon receipt of the green card.

No. it would not have any adverse impact on your adult child immigration papers.

Apply for COS for dependents. By law those under 18 cannot acrue unlaeful presence.

You should consult with a lawyer in private for optimal guidance.

I think you have a complex issue that warratns retaining a lawyer to counsel and follow through.