Hi
If you want to schedule (so that it runs automatically), then option (1) works best: you can schedule ABAP programs to run in the background, to be started at a certain time , or after a certain event.(using SM36/SM37)
Open (4) could also be schedule, but then this needs to be done outside SAP. Using Windows Task Scheduler or CRON job scheduling in case of unix/linux based systems.
Option (2) and (3) most of the time require "human intervention": you have to prepare the "data set" (which users/roles-assigments you are going to change), generate and start the BIM/CATT script