4.13. Can I enable/disable a system capability without modifying /etc/lids/lids.cap and reloading the configuration files?

Yes. However, this method will not save the changes past system shutdown. To enable a capability:
bash# lidsadm -S -- +CAP_SYS_ADMIN
To disable a capability:
bash# lidsadm -S -- -CAP_SYS_ADMIN