Move to iOS from Android
I used the setup feature to move to iOS from Android. After all of my old apps were installed i get popups every 5 seconds asking for my password. I was moving the firefox icon from my second page of apps to the first page, when the modal popped up and asked for my google account password. The firefox icon vanished, and didn't show up on any of my app pages. Then I long-pressed on another app on the second page to try moving it. Then the firefox icon reappeared on that page.
I think it would be best to combine the repetitive password request modals into a single notification that sits in the status bar and I can address when I have access to my password manager.
iPhone 8, iOS 11.1, Android 7.1.1 on previous device