>>281712420
>some abilities require both hands free don't allow him to use multiple abilities (?)
That's not a rule of his ability, just a consequence of its rules.
To use a nen ability, he needed to hold his book open with one hand. Logically, stolen abilities which require both hands then couldn't be used this way. Hence the introduction of the bookmark.
Nen after death is also not something he uses, just a weird interaction that can happen, if the original user dies with the right mindset, the stolen ability can persist in the book even beyond the original user's death. This is also not a rule of Chrollo's ability, just something that can sometimes happen.
