Step 2 (2018-01-19)
The extension has successfully passed the «Business Review» stage.
So, the «Business Review» stage took 1 day.
Now I am waiting for the AlphaCommerceHub Magento Marketplace submission process to finish, because currently the AlphaCommerceHub and SecurePayHub extensions consist of identical source code, and every submission issue with the AlphaCommerceHub extension will obviously affect the SecurePayHub extension too.