chris lz: I am not sure I understand what you are asking in your first question about "a controller looking at a radar scope is what they have in mind when they think of "confirmation from ground based aids.".
The rules for controllers to identify aircraft are strict and usually laid down in the company or local orders.
They may include confirmation of passing over a ground based aid like VOR that is marked on the video map, reporting a bearing and distance from an approved aid, by confirmation over a known geographic point marked on the video map, etc.
The list is not complete but you get the idea.
Re your second question, civil aircraft cannot receive bearing information from military Tacan, they can only get distance from the Dme.