I think Yami2 Awakening allows him to not just nullify DFs by touch but also directly extract-absorb them fruits himself. But in MF, BB hasnt mastered its application to the fullest so he needed some help like mystical cloak of darkness or something.
But even if he get Yami2 ability to absorb other DF, he will still die from eating 2 DFs so thats how his unusually different body structure came into play. Now about that i have no clue, maybe he got no sleep since his multiple personalities/genetic chimerism personas switching around in turns/cycles of being conscious/awake?
All in all BB is an extremely interesting character. I hope he gets Oda's full attention and focus regarding his character, not empty shenanigans without any substance.