Disaster, Kimber's Rebellion, Frame Up, Battle of the Bands. 
After this point she's shown with straight edged red pumps:

Starbright Part 1: Falling Star, Starbright Part 2: Colliding Stars, Starbright Part 3: Rising Star, The World Hunger Shindig, Adventure in China, The Music Awards Part 1, Broadway Magic, In Search of the Stolen Album, The Princess and the Singer, The Jem Jam Part 1, Culture Clash, The Talent Search Part 1, Scandal, The Bands Break Up, The Treasure Hunt, The Day the Music Died. 

Her outfit is pretty faithful to the doll's (the lapels being the main difference, as well as the shoes (they seem to be slides in the first five episodes of the cartoon). 
This fashion with a salon cape is a separate cel model number.

I had to guess at the hemline of the dress & the shoe style as they are not shown on the cartoon.

Kimber's Rebellion. 

Disaster. 

Kimber's Rebellion, Frame Up, Battle of the Bands, Starbright Part 1: Falling Star, Starbright Part 2: Colliding Stars, Adventure in China, Last Resorts, The Rock Fashion Book, In Search of the Stolen Album, The Princess and the Singer, The Jem Jam Part 2, Scandal, One Jem Too Many, The Bands Break Up, Danse Time, KJem, Hollywood Jem Part 1 (with black earrings), Homeland, Heartland, Straight From the Heart, A Father Should Be.... (black earrings)

The Jem Model sheet number for this fashion is K-2. 

Battle of the Bands, Starbright Part 1: Falling Star, Starbright Part 2: Colliding Stars, Starbright Part 3: Rising Star, In Stitches, The Music Awards Part 2, The Rock Fashion Book, Broadway Magic, In Search of the Stolen Album, One Jem Too Many,  The Bands Break Up, The Treasure Hunt, Journey To Shangri-La. 

The Jem Model sheet number for this fashion is K-4. 

Battle of the Bands, In Stitches, Island of Deception, Aztec Enchantment (maybe), The Jazz Player, Alone Again, Out of the Past, Straight From the Heart, Change of Heart. 

This is a song-only fashion and does not likely have a regular model sheet number. 

This is a song-only fashion and does not likely have a regular model sheet number. 

This is a song-only fashion and does not likely have a regular model sheet number. 

I guessed at the skirt length and shoes.

The Bands Break Up. 

Starbright Part 2: Colliding Stars, Starbright Part 3: Rising Star, The World Hunger Shindig, The Rock Fashion Book, The Jem Jam Part 2, The Talent Search Part 2. 

The Jem Model sheet number for this fashion is K-7. 

The Jem Model sheet number for this fashion is K-9.

The Jem Model sheet number for this fashion is K-10. 

Used with permission from Shevona.  See a scan of the actual cel model sheet (I have altered it to fit this page). 

The Jem Model sheet number for this fashion is K-11. 

Starbright Part 3: Rising Star. 

It's reasonably safe to guess that this fashion probably has the model sheet # of K-12.

The Music Awards Part 1, Glitter and Gold, Scandal, Father's Day, Rock 'N Roll Express, A Father Should Be....

The Jem Model sheet number for this fashion is K-13. 

Adventure in China, The Jem Jam Part 2, The Talent Search Part 2. 

The Jem Model sheet number for this fashion is K-14. 

Rock 'N Roll Express. 

The Jem Model sheet number for this fashion is K-15. 

In Stitches, The Music Awards Part 1, Broadway Magic, The Princess and the Singer, The Bands Break Up, Danse Time, Beauty and the Rock Promoter, Homeland, Heartland, The Day the Music Died. 

Thanks to Walter for the Model sheet to this fashion!

The Jem Model sheet number for this fashion is K-6.  It would have been available for use as early as the Starbright series but wasn't used until this episode.