Do you know where Ryan's gps is? That little standalone unit that attaches to the phone via bluetooth is actually really good. You don't have to have the phone on you unless you want to see times while riding.
Nope
ADVANCED and INTERMEDIATE GROUP riders MUST wear a back protector designed for motorcycle competition in lieu of, or in addition to, the standard back padding in their suit.
54 will be to big. I'm 5'9" with a 31" inseam and my 56 is just a touch big on the reach from the seat to the bars, I should have purchased a 54. IP is better at sizing than I am so I'm sure he can get you close.
Have you been to a bike shop for sizing?