Yeah, whenever you do that and install a Brave browser, it creates a new wallet ID for your device. It’s typically been recommended you not do this. That said, they are not far from eliminating the wallet limit, so this is only talking about present and past.
Yes, yes it does.
Not on your own, but you can fill out the Wallet unlinking request form to have it unlinked. Further details can be seen at Unable to re-verify wallet - #118 by Mattches