Hi Pixie Dust,
I once had a lot of time on my hands so I went through this whole thread looking for advice. It seemed as though people said not to wear contacts so you go in looking like yourself. If they like you for a certain role but you have the wrong colour eyes, they may give you coloured contacts to wear while you perform. This isn't official info though just what I have read.
As for the nose, it's really hard to say. No one can know exactly what the casting directors are looking for so I would say just go and audition and see what happens! If you don't get cast right away don't be too discouraged. I've been to 5 Disney Cruise Line Auditions and have not yet been cast and I know people go to tonnes of auditions sometimes before being cast. Just go for the experience and have fun!
Best of luck to you!!