One way: create a group in fop2admin that does not include those buttons, and then assign the group to all your users.

Another way (need access to the command line and know what you are doing): modify autoconfig-buttons-freepbx.sh and setup the mysql query as to not include trunks or park type buttons.

operator.css can also work, you can set display:none to the trunk and park divs in index.html

Best regards,