Upon reboot, the phone should set up normally without asking for the previous Google account.
No. Most methods labeled "zaggarxyz frp" are free community solutions. Beware of scammers offering paid remote unlocking under this name.
Note: Instructions vary by device model and Android version. The following is a generic guide based on popular ZaggarXYZ methods.
No. In fact, a hard reset from recovery triggers FRP. It does not remove it.