Seems like an easy enough split. Scrooge takes the coins, Rarity takes the gems, Ego gets the rest as payment for making this awesome crossover happen. Everybody wins!
if it only would be that simple, rarity will take all the gems but scrooge is too greedy and starts to chase rarity all the way to ponyville and then there will be deathmatch between DD universe and MLP universe and it ends when celestia sends scrooge to the moon
You do know that Scrooge McDuck badass that he is can survive on the Moon right? I take it you never played Ducktales The Video Game