I can't speak from experience on the guest side of things, as I've never traveled to WDW with anyone so close to the height requirements. Having been on the opposite side as a ride operator at a (different) amusement park, though, I'll warn you that it's going to be ride-by-ride whether it's a yes or no from cast members. They have to check every time, and it's possible for a kid to measure tall enough one time and not the next time. Keep in mind that everyone tends to get slightly shorter as the day goes on and cartilage gets compressed by being upright and moving around, and variation in shoes, posture, etc. can mess things up. My guess is that she should be able to ride, but I would set her (and your) expectations low--work from the baseline that no is normal and yes is a bonus to avoid major disappointment, and plan how you'll handle it if it's a no-go at any point (using child swap, the whole family moving on to a different ride, or however you want to handle it).