Your form changes will only be visible in a user topic after it has been saved. Please keep the UserRegistration form and the user form definition in sync. When you update the user form you need to edit/save the System.NewUserTemplate (not recommended, see below). This ensures that the fields are in the right order.
If you use a custom user form, you ought to use a custom 'new user' template as well. This will make your changes safe to future Foswiki upgrades.
To create your custom new user template, do this: