while you wait for my colleague to take over let me try to help.
- Go to WPML → String Translation.
- Scroll to the bottom of the page and click the Translate texts in admin screens link.
- This takes you to a searchable list of admin strings. Select your string and click Add to String Translation.
- You should now see and be able to translate the strings on the String Translation page.
The Header and Footer are created as custom post types, both were set to "Not Translatable" in the WPML settings.
I changed the settings and now they're available for translation. Please go to Dashboard > Footer Builder, and click the + sign to translate the original footer.