H4 Visa Port of entry question

My Wife is on H4 and she has valid visa till September 2017 and we have filed extensions for both of us in Jan when i am filing for my ammendment. When it is in pending she left to india and it got approved while she is in india. She is coming back in a week and I already sent her approval for i539. our current i94s were extended till Feb 2018. When she arrive at port of entry, should she show her latest i539 till Feb 2018 ? or Should she just show my latest i797 that has validity till Feb 2018 ?

If she show her latest approval for i539 that has validity till Feb 2018 on her old i94, will they extend this new i94 till Feb 2018 ?

Please help me out.