The calendar operates a bit differently than other tools. Local units have control of who has edit rights. It's preferred that it be granted by standard calling, that way it will transfer to the new person automatically. Access can also be granted "by name", but it's up to the unit to keep the assignments up to date. As far as I know, access can't be granted by custom calling.
I believe all activities have to be approved by the bishopric, so it's possible the unit would prefer someone in the bishopric/clerk/secretary adds the events.
Discuss questions around local unit policies for membership (creating records, transferring records, etc.) This forum should not contain specific financial or membership information.