The Ultima blades (all of them I believe) have an 8" rocker. That should make her jumps more stable, but might make spinning more difficult (or so goes the rocker theory...)
The Legacy has a cross cut toepick, and I think the other Ultima blade you mentioned does too. It takes a little bit of getting used to, but when I had one I liked it. Switching back to straight cut, I didn't notice the difference. I plan to go back to cross cut soon. The coach I talked to last night says she doesn't like for her skaters to have straight cut anymore, but didn't really say why she prefers cross-cut.
I kind of agree with dak that kids are resilient, and unless you tell her the transition is going to suck, she'll probably just put on the boots and go for it. Spins will be the hardest thing. (I love getting new blades for turns- it feels like the turns just do themselves...everything else takes me awhile to adjust to.)