If I live in SC is it okay to do SC taxes first?

probably not.  some data flows from federal return and then if you enter data for SC that flows from fed, it will be treated as an override and TT will prevent e-filing  

Information flows from your federal return to your state return.  If you have two state returns to prepare, you need to prepare the non-resident state first.  And...you cannot e-file a state return unless the federal return has been e-filed and accepted.