Fei Wong Reed's intention was to scatter Sakura's feathers across many worlds to force her to travel between worlds to collect them. It's not just the heart that remembers... there are memories of the body, as well. He wanted her body's memories of the worlds, like a 'map', to grant his own wish. I do not know what that wish was yet.
It's dangerous, to travel like that, so... the princess would need companions to protect her. Fay-san and Kurogane-san were not travelling with her by chance, but rather by his design. I refused, so he simply made a copy.