A ceremony without the flower girl? If she is related that might be difficult to explain especially if you've already asked. She could do her duty and the go to the kids club for the reception. Guests should understand that.
Sometimes the airline may offer a better choice, depending on how much stuff you want to ship, taking an extra check-in baggage, may be the easiest choice.
A large flat dish with water and rocks, that you could colour to match your theme, with floating candles and maybe a few fresh flower petals. Saw this at a friends wedding