We faced a similar problem with consultants on an old AWS account that had become obsolete. A week of back-and-forth with support ensued as we tried to figure out how to close the account. The process seemed excessively complicated since the only way to remove the consultants, who were merely members and not admins, required them to add a billing method first. It felt unreasonable.
Ultimately, we were able to close the account with the consultants' cooperation.
I get your point that it's wise to remove consultants promptly after their contract concludes, and I agree. However, this doesn't take away from the fact that AWS's account closing policies appear to be less than user-friendly.
