hmm...
it can't be totally rocky
so there left: woody,pin,needle,coiny,sb,eraser,pencil,bubble,firey,tb,gb and flower
flower loves blocky (blocky is dead) so flower can't be it
woody loves td (td is dead) so woody can't be it
firey loves leafy (leafy is dead) so he can't be
PEN,MATCH and IC friends were: eraser,pencil and bubble
THERE LEFT: PIN,NEEDLE,COINY,SB,TB, AND GB
in episode IDK NUMBER there was a book "bfdi tips and tricks" made of course by gb. so she can be it
pin is most neutral here (i mean she is the only one who didn't got many screentimes) she can be murderer to.
also gb and tb can work together and make like robo arms or something
LEFT: PIN,GB and TB
we have chance that sb wanted everyone think gb is murderer