Hi Joseph,
No worries my friend
In Unity Connection (and Unity) changes made at the Template level
are not retroactive and will only be applied to users that are created
after the Template change so that won't work here
Bulk Edit will be your good friend here.
Bulk Edit changed in 8.x from where it was accessed in 7.x.
Here's a clip that speaks to how this is run now. You first search and select all
the users you want to change and then choose Bulk Edit;
To Edit User Account Information in Bulk Edit Mode (some editing from original)
****This would be for changing the Caller Input but you will see the Message Send option in Bulk edit as well****
Step 1 
In Cisco Unity Connection Administration, on the Search Users page, check the applicable user check boxes, and select Bulk Edit.
If the user accounts that you want to edit in bulk do not all appear on one Search page, check all applicable check boxes on the first page, then go to the next page and check all applicable check boxes, and so on, until you have selected all applicable users. Then select Bulk Edit.
Step 2 On the Edit Caller Input page, change settings as applicable.
Note The Status message at the top of the Edit Caller Input page tells you how many user accounts are being edited. Also note that the page is populated only with the fields that you are allowed to edit in bulk mode, and that the fields available for edit also depend on whether all of the user accounts reside on the local server.
Step 3 If applicable, set the Bulk Edit Task Scheduling Fields to schedule the Bulk Edit operation for a later date and/or time.
Step 4 Select Submit.
Step 5 If applicable, continue to change settings for these user accounts on the related pages available from the Edit menu. As you make changes on each page, select Submit before going on to the next page to make additional changes.
Try a couple of test users first to come up with the exact plan.
Cheers!
Rob
"go easy...step lightly...stay free "
- The Clash
