However, Rulodia is not a star of destiny so if you waste a Listening Crystal on Rulodia you will be missing out on one of the stars. Also note that you pretty much have to use a Listening Crystal on Feather so that you can recruit Ayda (if you are getting all 108 stars). After that, you can use a Listening Crystal on Abizboah or Siegfried, it doesn’t matter, as they both count towards the 108 Stars of Destiny. Muku Muku is the first optional recruit.
The first time you return to Kyaro, do not go straight to Genkaku’s house. Instead, go to the tree just east and north of the house and search it three times. Muku Muku will join you here, and he is actually quite useful in the early stages of the game. You can also recruit MukuMuku on the path between Greenhill and Muse (or maybe between Greenhill and Matilda, I forget).