None can be removed at the MFP.
To remove the Default go to :
Properties>Services>Workflow Scanning>Display Settings and it should be down at the bottom to remove it.
Now the one that ends with TWAIN unless you created that somewhere on the device is generated by the TWAIN/WIA driver on a PC, you need to remove the TWAIN device at the PC it got installed on so it will stop pushing the template to the device
Otherwise Cheryl's post is correct and the templates will be there as that is where they are created, modified and deleted.
If none of that gets you where you need to be, the device(s) would have to be wiped by a tech back to the defaults.