The * next to a keybind means that it was changed from the default key. The game may be showing you E and Alt because those were the default keys for those actions before they were changed.
E is primary. If E takes you to some other dialog then F is secondary (I suppose in case you had pressed E multiple times and hadn't wanted to accept the main option in the second dialog). I guess tertiary would be for when the secondary dialog brings up yet another dialog.
And I'm not talking about options in conversation, where you can spam E to get through it quickly, but rather to dialog options where there's no going back, such as pressing E to queue for a Cyrodiil campaign and then pressing F to accept the transfer to Cyrodiil when the queue pops.
I guess something like converting Crown Crate loot into Crown Gems would be another example where the confirmation of the primary response needs to be a different keybind to safeguard against accidentally converting something into Crown Gems.