Don’t pardoned people by definition need to have been convicted of a crime whether real or in some select instances otherwise? Can you pardon someone not convicted of a (federal) crime?
Preemptive pardons have been used in recent history.
https://www.criminallawlibraryblog.com/amp/preemptive-pardon...
Yes, the last president pardoned himself and his family on his way out.
Not according to Ex parte Garland (1866).
> 9. The power of pardon conferred by the Constitution upon the President is unlimited except in cases of impeachment. It extends to every offence known to the law, and may be exercised at any time after its commission, either before legal proceedings are taken or during their pendency, or after conviction and judgment. The power is not subject to legislative control.
https://tile.loc.gov/storage-services/service/ll/usrep/usrep...
Basically you can't pardon acts that haven't happened yet, but you can pardon before any legal action has been taken on prior acts.