If the prefix url is prefix.com/, that is all you need to put in the prefix url setting. No need to use the ? question mark. It's just adding the prefix immediately before the url.
Thank you for reporting. This is a big more complex and I will need time to look into this bug. Unfortunately the only other work around right now would be to disable the Forms app while copying groups.
Thank you for reporting. I should be able to add some kind of provision in there for existing announcements, so you don't have to manually adjust existing announcements unless needed.
Noted this suggestion!
That looks like another widget from another app? Which one are you using?
Yeah as mentioned above, you'll need to submit a custom request to the app author to add support for the Portal.
Display a members secondary groups in select locations throughout the forum. Including topic, hovercard and profile view. Select which secondary groups display and the order in which they display.