Comodo does not require any other verification procedures for PositiveSSL and EssentialSSL Certificates other than validation of your domain ownership. It can be done by either receiving the validation email or uploading a certain .txt file to the root folder of your website or adding a certain CNAME record to the DNS zone of your domain. It means that there should be no delays in issuance of PositiveSSL or EssentialSSL. If your certificate is not delivered in 2 hours since you approved the approver email, please contact our SSL Support Team for assistance.
You can read more details about verifying domain ownership for these certificates here.