Currently, it's not possible to bulk edit custom fields on Approvals and To-dos.
Time consuming to update custom fields across multiple approvals or to-dos. They either have to be done manually, or via a CSV update, or API.
Allow the in-app bulk edit to include custom fields, so users can quickly make updates via the UI.
Thanks for adding this Ben. To clarify - the request is really to enable the same action, field, custom field bulk edit ability across all record types and field types, not just approvals.