It seems a bit ridiculous that they keep adding costs- they need to be upfront about these things.
I'd also say that a $75 "rental fee" is a bit high for a costume, but I've been in dance performances that charge $50 for a costume you don't get to keep. It pays for the original purchase, cleaning, alterations, and upkeep. Depending on what the costume is, $75, may be reasonable... like if the costume costs $200... If the club is NOT subsidizing the cost of the costume, as well as cleaning and altering it, I'd insist on keeping it.
The $100 fee is in line with other ice shows I've been in - I paid $75 to skate in a local show, that included a group number, plus the opening/finale. Costumes were seperate, but simple- I don't think I spent more than $100 in costumes for all 3. Those fees cover rehearsal ice, show ice, coaches fees, music cutting, lights, taking the hockey glass down etc. It sounds like your club is trying to put on a professional show. That club got lucky they didn't have to rent the ice for 2 straight days because once props are up and the glass is down, no one else can use it- but the arena didn't charge for the full time the rink was down! Thank goodness.
But $700 per kid is insane. How many numbers are they in?
Maybe someone needs to get to the board meeting and tell them the parents want a no frills show! My current rink's club does those- no lights, no professional music editing, hockey glass stays up, kids provide their own costumes, groups usually just do pants and a matching t-shirt. The fee is $10 for a group number and $30 for a solo, with a $10 added fee if you aren't a club member.