Yeah you can either try to make it all work with the bigger girl getting the real experience and the others hangers-on. That might work? But yeah, its not for little little girls.
You can also substitute something for the littler ones and make it a special thing for the older.
My daughter would NOT have sat that long, that still, through that much hair pulling at those ages. She did it when she had just turned 6 and it was perfect, she remembers it and loved it and it was "worth it". We made it a mommy daughter thing and my husband and son went and had guy time (I believe they rode the speedway and then did buzz on repeat).
I will say - on my daughter's just-barely-3 trip - my SIL bought a couple cute mickey rhinestone barrettes and a little teeny crown and spent five minutes on a "makeover" in our room before we went to MK and my daughter still felt like a million bucks because the cast members made just as big a deal out of her as any of the BBB kiddos. Plus, it was WAY cheaper and when she wanted the crown off because it hurt and the bun out because it hurt and to wash her lip gloss off it wasn't like we had this whole big investment...it was just, meh, okay! You could do that for all three, and make things age-appropriate, and it might be better if the goal is everyone feeling similarly treated.