Nobody where we are uses the matrix blades, so can't comment, nobody uses parabolic. The whole "too much blade" thing is a great debate - some advocate going straight to a top level blade, some say hold off.
I will say that, having moved off of Ultimas, which we did love for price and that, we have discovered that skating has improved tremendously. We had been told - here and elsewhere - that the Ultimas were notorious for "scratchy" and "noisy" edges, and we have definitely seen huge improvements in terms of losing that comment on test sheets since we've gone to a Wilson blade. It's not a change in the skater, it's definitely the blade - we have silent turns and real "edge rip" instead of noise. I know, other skaters will have different experiences - just putting down ours. We also found that cross-cut picks were better than straight cut ... but lots of people prefer straight cut, like on the Pattern 99's.
If you go the Freestyle, you can't go back - it's a high end blade. Also, there will be quite a period of adjustment for her, so, if you're going into tests or competitions, you may be losing a significant amount of training time during the transition. I would go with what YOUR coach recommends - not other coaches - after all, you picked him/her as your coach, right? And you should use the equipment they recommend.
The Legacy discussed is roughly a CoroAce in the Wilson blades: I've never heard anyone say anything negative about these blades!
Weight on blades is nominal. If you're talking about a small girl, the weight saving can be important; however, we found the heaviest thing on the feet were the boots, not the blades.