Joe has answered your original question about the sequence. He said that the sequence is not important. Webmin does not prevent a user from accessing a database if the user was created after the database was created. And vice versa. So dont worry unduly about sequence.
Please start a new topic if the original topic has been covered, do not discuss multiple topics in the same thread. This helps the community in future searches for information. See:
The best thing for you to do would be to switch from Webmin to Virtualmin. You will then be able to host websites like a champ and WordPress with a single click.