I also thought about that! (≧∀≦) Was it ever specified what kind or which prince they have to marry? Maybe there's a prince for all 7 candidates? The white haired guy could be the prince of gardening and uncle Owen could be the prince of middle-aged hunks! ε=ε=(ノ≧∇≦)ノ
Is that the ONLY prince? Why can't they just marry a different prince? Maybe the gardener's a secret prince...hopefully? ...he's hot(づ ̄ ³ ̄)づ