Reddit reviews Jazz Conception -- Flute: 21 Solo Etudes for Jazz Phrasing, Interpretation, and Improvisation (English/French/German Language Edition) (Book & MP3 CD)

All of the 130+ volumes of the Aebersold play-along series have lead sheets in C, Bb, Eb, and bass clef transpositions, and include one or more CDs of recorded rhythm sections to play along with. If you know of a few of her favorite artists or jazz tunes, you can find books which include them in the Play-along index. All the songs include multiple choruses with the rhythm section, so she'll have the opportunity to play the melody and a few solo choruses for improvising.

If you're looking for something more instructional, I'm a huge fan of Jim Snidero's Jazz Conception series. In those books, a number of popular jazz standards are given with pre-written solos that emphasize learning jazz articulation and scale/chord choices. They also include playalong tracks, both with the specific instrument performing the written solo and a rhythm-only track so that she can play along on her own, either with the written solo or her own improvisation.