That order makes sense, and I’d note it against GLWO-19. Nothing is changed now.

Why it helps

• Account details come first and the optional extras come last, like most sign-ups.
• The wizard keeps every answer in the browser and sends them once, so reordering the screens doesn’t affect what the server receives.
• The server side is mostly ready. provision.php already accepts a username field and checks its format (3–60 characters, letters, numbers, _, ., -). The theme’s setup code already renames the login account when a username is supplied.

Things to settle when we build it.

• Inherited username: if no username is given, the new site keeps the account name inherited from the template, which on your sites is probably sca40annv. The welcome email says bloghost_admin, so the two disagree. Making the username required fixes this at the source.
• Reserved names: I’d refuse admin, administrator and bloghost_admin, since the goal is a login that isn’t guessable.
• Pushover last: it’s the only step that sends people off to another site and app. Since the wizard holds state in the browser, going out and coming back is safe. I’d make skipping it obvious, so nobody feels stuck there.
• Details to update: the progress dots and back buttons, the ZeptoMail welcome email (so it shows the username they chose), and the bypass test link, which should keep working.
• Rename: bh-subdomain-rename.php would need to carry the chosen username across, which it doesn’t yet do.

I’d treat this as a self-contained change to start.php and a small one to provision.php. Tell me when you want it built.