Yes, you can rename a Librarian member via batch.
JCL example below::
//S1 EXEC PGM=AFOLIBR,PARM='NRJS,NJTA'
//SYSPRINT DD SYSOUT=*
//OSJOB DD DUMMY
//LIST DD SYSOUT=*
//INDEX DD SYSOUT=*
//MASTER DD DSN=YOUR.LIBRARIAN.MASTER.FILE,DISP=SHR
//SYSIN DD *
-SEL OLDMEMBER,RENAME=NEWMEMBER
-END
/*
//