From the most recent version of EA’s language raws that I bunched together a while back:
##Makes the B button locked (not able to be used to skip convos?)
LCKB, 0x87, 4, -game:FE7 -indexMode:8
##Makes the start button locked
LCKS, 0x89, 4, -game:FE7 -indexMode:8
##Unlocks the B and start button.
ULCK, 0x8A, 4, -game:FE7 -indexMode:8
##Makes player unable to use start to skip the event.
NEVENTS, 0x8C, 4, -game:FE7 -indexMode:8
#Alias
NSSP, 0x8C, 4, -game:FE7 -indexMode:8
##Makes player unable to skip convo with B button.
NCONVOS, 0x8D, 4, -game:FE7 -indexMode:8
#Alias
NCSP, 0x8D, 4, -game:FE7 -indexMode:8