RE: Access to Vendor E-mail Options window
Right, I would agree that there is no separate Email Option task that is specific to vendors, but this is the same situation with the Internet Information window. There is only one task (under MD GP > Windows > Company). However, that task just happens to be included in CARD_0301, whereas the Email Option task does not.
A user who only has access to Purchasing and not Sales, can still click on the drop-down within the Internet Information window to select Customers, and can edit the Internet Information for customers as well. I guess it's just a matter of whether a user would know to try this, and/or if there is any harm in it. In our case, we didn't care if they had this access or not, so we just made the EMAIL task that I created to all relevant roles (AR Clerk, AP Clerk, etc).
Also note that if you only have the Email Option selected (as is the case with the Default User task), this will give you access to the Vendor Email Options screen, but it will not allow you to use the Message ID lookup in order to change the Message ID within that screen.