Hey there.... congrats on going to perform in the parade!!!:sohappy::sohappy::sohappy:
You will have a lot of fun.
I'm a multi parade veteran of Main-street from Virginia. (
being the son of a high school band director has its advantages) I've marched with my high school twice and with the Marching Virginians of Virginia Tech once.
First off...to answer your last question, yes you will be backstage... behind Splash Mountain and Pirates of the Caribbean. My parade experiences always started us from Splash Mountain and exited at the front of Main Street. You'll be amazed how quickly you will get from the end of the parade route on Main Street to the backside of Splash Mountain. You'll see all the parade floats for the evening that are stationed back there... and will probably see characters without their heads.
We also got a clinic with the chief director of music for Disney world. We got a taste of what goes on in a recording studio when we also dubbed a the Whole New World sound track for Aladdin.
One memory that really sticks out for me during the parade was after we rounded the circle from the castle onto the top of Main Street. We were into our marching drum cadence when our drum major at the front gave the high sign to start the next song... well only two in our drum started the roll-off... and then it got eerily quiet...

The percussion section got confused, fouled up, and stopped keeping the beat. This lasted what seemed like hours... when everyone watching knows the band screwed up and we were sweating bullets... Fortunately... one of them got us back on cadence and continued performing down Main Street. That was quite embarrassing!! Imagine... a marching band.. marching in a parade with no drum cadence??
Anyways... that was a mini-disaster and I'm sure your's will be better. Of course you can't take pictures backstage... but there isn't a whole lot that is interesting with what you will see. The best way to see all of the backstage is to take the Keys to the Kingdom Tour. The Backstage Magic Tour is great as well.