The hair won't help... The CM's will most likely push it down anyway. You can try the shoes if you want to, but the height requirements are there for a reason. (don't mean to sound harsh, but it's true...) She may be sad, but I think it's better to be safe than sorry.
Plus..... It will give you another reason to plan another trip! We went last year, and we told our son we would go back when he was tall enough for Space Mountain. It got him excited about planning another trip (knowing we definitely WOULD go back in the near future), and as soon as he reached that milestone, we booked our hotel room and flights. We're going next month and he'll get to ride both Space Mountain and Mission:Space!