I would go fork first and seatpost last. Maybe bars 2nd and stem 3rd. I think you will get both the best performance and visual upgrade for the $ in the fork.

The cockpit is something she will be looking at all the time when riding so it makes sense to upgrade it to give her that "new bike" feel.

Heck, on a drop bar bike, it is amazing how much of an "upgrade" even new tape can be.