There are 2 types of templates: initial and updating. If you create Service Profiles from a initial template, SP and template are not connected; eg. making changes to template, will not update the SP's. This is different for updating template, where changes to template will update all derived SP's.
Adding or removing vnic's from a VIC I/O adaptor is disruptive, and requires a reboot of the blade. (adding / removing Vlan's is not disruptive, however).
In any case, you should implement a "maintenance policy", adding it to all SP's, and set it to ACK; in case of a change which requires a reboot, you get a pending activity, where you have to ACK every server that has to be rebooted.
Hope that helps
Walter.