I think Promo Coupon can be also applied later, It might be ignored cause it has expired. About the root password they said that they fixed it, you can also setup ssh keys for faster setup, see guide bellow.
SSH keys provide a more secure way of logging into a virtual private server with SSH than using a password alone. With SSH keys, users can log into a server without a password. This tutorial explains how to generate, use, and upload an SSH Key Pair.