If you do Emil's determination but then chapter select the part will still be there, have no fear

Third Location is wrong. You cannot visit Emil's Residence after completing his Determination Quest anymore. The door will simply be locked.

Second location is not clear, boss name is Ko-Shi, not Boku-Shi. The tower is the one you enter near the end of the game, reading that description one might think at the metallic tower near Pascal's village entrance in the city ruins, after the boss fight with 2B or 9S. Altough it's pretty easy to find I missed it the first time since I went directly to the book.

Tip for farming from the golden bunny - use the "blade" pod program to wake him up (works really well with three pods, will generally cause the bunny to wake up in a few seconds), and make sure you switch between A2 and 9S/2B when farming him, which will up the chances of him dropping the part.

Farmed him with 9s for lvl 99. Awakened him with damage chips, switched to exp and 80% drop rate chips. Lvl 62-99 i got 10 Powerup Part L. (which is 10 kills...)

I've tried at the Amusement Park Rabbit but I always got Machine Core instead of Powerup Part L. I even tried reloading and defeat the Rabbit again and again but never got it. Anyone know why?

Después de farmear experiencia con el consejo del parque desde nivel 80 para subir al nivel a 99, obtuve 6 potenciadores v3, de esos enfrentamientos soltó potenciadores 2 veces consecutivas/After farming experience with Park rabbit from level 80 to raise the level to 99, I got 6 Powerup Part L, from those clashes released Powerup 2 consecutive times

Is anyone else dying to this rabbit in one hit? Starting to feel like a total nub.

For the rabbit powerpart L I think you only get the drops when you dont have any in your inventory. When you have one in your inventory you seem to just get cores.