Under more details, there is a box called "Surname" I want to change this to say "Last Name" (A more common naming convention for the US. I have explored the code and can't find where this is located anywhere... Can anyone help?
You can do that with language customization. https://docs.moodle.org/310/en/Language_customisation
There should be about 9 or 10 places in the US English language pack you will need to see about changing.