A customer asked us to erase their data. Does the edit history keep it?

Not after the request. History keeps the previous value of each cell a save changed, and on the Orders and Reviews editors that can be a customer's name, address, phone number or email. Tools → Erase Personal Data takes that person's orders and reviews out of every history point, and a point left empty is deleted. An order WooCommerce has anonymised is also never changed by Undo or Revert, so the old details cannot be put back on it. Saved views and kept filters are searched too: wherever one holds the customer's email address, the address is taken out. A view that filters on their name or phone number is not found that way, so delete it yourself.