Where do I change the wording "membership fee total?"
It should work with Word Replacements, even for receipts. Under Administer - customize - Word Replacements.

UPDATE: Under Administer - CiviMail - Message Templates, then on the System Workflow tab, there's two receipts for memberships. You can edit it in there. If it's hard to find the wording use CTRL-F and search for Membership Fee.
Once in a while an upgrade will warn you that the template has changed and you'll need to merge the changes, but doesn't happen too often.