F1 approved at Home Country Consulate while H4 pending

Hi all,

Here is the current situation of my wife :

  1. Nov 2018 - Applied for H4 transfer for my wife ( as a part of my H1B transfer ). Application still in PENDING state.

  2. Dec 2018 - Wife travelled outside US ( while the H4 transfer is still pending ) and got her F1 student visa approved.

Now my questions being,

  1. When my wife returns to US before the H4 gets approved, which Visa would she be in ?

  2. If the H4 gets approved at a later date, would that Nullify her F1 visa ?. The aim is to keep her status in F1.

Any help would be greatly appreciated.