Ah my bad I meant to ask if you were using their "id" numbers. Since mewtwo and roy use the cosmetic "id" for petey(what the tutorial uses) and rayquaza, your new slot may be conflicting with whats already setup in project m. Just my guess, you could try other boss ids and see what happens.
and for reference these are the id numbers already assigned
Mewtwo
Fighter26 (Unused Mewtwo)
Slot33 (Petey)
CSSslot2E (Rayquaza)
Cosmetic2E (Rayquaza)
Roy
Fighter27 (Unused Roy)
Slot32 (Mario Debug)
CSSslot2D (Petey)
Cosmetic2D (Petey)
and for reference these are the id numbers already assigned
Mewtwo
Fighter26 (Unused Mewtwo)
Slot33 (Petey)
CSSslot2E (Rayquaza)
Cosmetic2E (Rayquaza)
Roy
Fighter27 (Unused Roy)
Slot32 (Mario Debug)
CSSslot2D (Petey)
Cosmetic2D (Petey)
