adding extra elements will work. But if you change the base, and the new element dont have same names, then it will fail. The names are hard-coded.
here is the list of controls:
gearFK = [
u"body_C0_ctl",
u"leg_L0_fk0_ctl",
u"leg_L0_fk1_ctl",
u"leg_L0_fk2_ctl",
u"foot_L0_fk0_ctl",
u"leg_R0_fk0_ctl",
u"leg_R0_fk1_ctl",
u"leg_R0_fk2_ctl",
u"foot_R0_fk0_ctl",
u"spine_C0_fk0_ctl",
u"spine_C0_fk1_ctl",
u"spine_C0_fk2_ctl",
u"shoulder_L0_ctl",
u"arm_L0_fk0_ctl",
u"arm_L0_fk1_ctl",
u"arm_L0_fk2_ctl",
u"thumb_L0_fk0_ctl",
u"thumb_L0_fk1_ctl",
u"thumb_L0_fk2_ctl",
u"finger_L0_fk0_ctl",
u"finger_L0_fk1_ctl",
u"finger_L0_fk2_ctl",
u"finger_L1_fk0_ctl",
u"finger_L1_fk1_ctl",
u"finger_L1_fk2_ctl",
u"finger_L2_fk0_ctl",
u"finger_L2_fk1_ctl",
u"finger_L2_fk2_ctl",
u"finger_L3_fk0_ctl",
u"finger_L3_fk1_ctl",
u"finger_L3_fk2_ctl",
u"shoulder_R0_ctl",
u"arm_R0_fk0_ctl",
u"arm_R0_fk1_ctl",
u"arm_R0_fk2_ctl",
u"thumb_R0_fk0_ctl",
u"thumb_R0_fk1_ctl",
u"thumb_R0_fk2_ctl",
u"finger_R0_fk0_ctl",
u"finger_R0_fk1_ctl",
u"finger_R0_fk2_ctl",
u"finger_R1_fk0_ctl",
u"finger_R1_fk1_ctl",
u"finger_R1_fk2_ctl",
u"finger_R2_fk0_ctl",
u"finger_R2_fk1_ctl",
u"finger_R2_fk2_ctl",
u"finger_R3_fk0_ctl",
u"finger_R3_fk1_ctl",
u"finger_R3_fk2_ctl",
u"neck_C0_fk0_ctl",
u"neck_C0_fk1_ctl",
u"neck_C0_head_ctl"
]
alignFK = [
u"arm_L0_fk2_ctl",
u"arm_L0_ikcns_ctl",
u"arm_L0_fk1_ctl",
u"arm_R0_fk2_ctl",
u"arm_R0_ikcns_ctl",
u"arm_R0_fk1_ctl"]
alignIK = [
u"arm_L0_ikcns_ctl",
u"arm_L0_ik_ctl",
u"arm_L0_upv_ctl",
u"arm_R0_ikcns_ctl",
u"arm_R0_ik_ctl",
u"arm_R0_upv_ctl"
]
gearIK = [
u"leg_L0_ik_ctl",
u"leg_R0_ik_ctl",
u"leg_L0_upv_ctl",
u"leg_R0_upv_ctl",
u"arm_L0_ik_ctl",
u"arm_L0_upv_ctl",
u"arm_R0_ik_ctl",
u"arm_R0_upv_ctl",
u"leg_L0_mid_ctl",
u"leg_R0_mid_ctl",
u"arm_L0_mid_ctl",
u"arm_R0_mid_ctl"
]