Also not knocking teachers (married to one) and I disagree completely with your daughters instruction to stay off the mic... but I can understand the teacher's logic regarding this... Have you ever seen kids exposed to some new form of technology for the first time?!? Holy cow, one of those "ring bell for service" things suddenly become a full on drum circle to a 10 year old kid... and the same kid faced with the possibility of playing with the proximity effect of most cheap mics you find in schools?!?... there's not enough Excedrin in the world. I'D do everything in my power to restrict that behavior as well! Can't blame them for trying, but it's still improper technique. >Rant off.<
I agree with almost everyone here that she needs to be more on the mic for live vocals, in a studio situation being off the mic a little is not nearly as big of a deal. But when you are on stage in a live situation as said before loudest at the mic wins.
Any of those mics you already have should work just fine. I tend to find the sennheiser 835 to have a little more mid presence than the shure 58s IMO. In the same price range.