From Trésor de la Langue Français, 19th c. :
Régent : "Celui, celle qui exerce le pouvoir, qui gouverne un état durant la minorité du souverain ou dans certaines circonstances exceptionnelles où il en est empêché (incapacité, absence). "
Regent as technical term is improper, since François II did not interrupt his reign during Tyrol's popular uprising (Aufstand).
A delegation of power for subset of the Kingdom/Empire, while the sovereign is still in charge, is a Lieutenance, Governorat, Vice-Royauté, not a Régence. Except for napoleonic France, it is always granted to a person of royal lineage or high nobility.
And, without a formal title provided by Austrian Court, Hoffer was technically the chosen leader of an uprising, which gave, by the law of the time, no protection against neither French occupation force nor new province owner, Bavaria.
But perhaps you gave him a title to avoid to recognize that, being an uprising's leader without government approval, his execution was no more a murder than those of Irish, Polish, or other national leaders ?