You might want to proofread your post - there is no "Riedell Blue Star" skate. Maybe you meant "Blue Ribbon?" That's the equivalent of the Riedell 121 RS, which is a rec skate. Since the skater is already landing flips, lutzes and doing back camels, she's beyond the usage for that model.
Riedell LS is a strange thing - it used to be a boot model, then they used it to group their skates into a "Learning Series." Those were skates for low-level freestyle skaters. Now, only the 910 LS still has the suffix, but they have two "Light Series" boots (LS 2010 and LS 1310) with the "LS" prefix. It's very confusing, lol. Any of the current Reidells with LS would be too stiff for this skater - she'd never break in the boot.
Have you inquired with her coach? Or your local pro shop? This would be a lot better than asking us. Every skater different.
The OP is the coach, lol. I pester the pro shops when I visit because I learn something new every single time. Sometimes, the information conflicts with other things I've learned/been told, so you have to get input from multiple sources and ferret out the correct information.
I have a petite 9-yo student with a variety of spins, including a wonky catchfoot and a very-high back sit spin. She's landed a loop but hasn't landed a flip or lutz yet. (Close but she doesn't check properly through the jump, so it's not the skate's fault.
) Her spins improved drastically when she moved from the 121 RS to the 133 RS. I think the stock Quest Onyx blade was the main reason; even her mom said that she loved the blade.
In the Jackson line, I'd suggest the Classique model because she's already landing the singles and will need a more durable boot than the Artiste. The blade's comparable imo, but our skate fitter said that she thinks the Artiste's Mark IV blade is slightly better than the Classique's Mirage. I compared them and they look the same to me, but there is a price difference between the two blades. Perhaps the Mark IV's being cleared out of inventory to make way for a less-expensive alternative? *shrugs*
What brand/model of skates is she wearing now? I usually suggest staying with the same brand if there are no complaints or issues.