Haha, I’m sorry if I came off a little mean after “leech king” (I’m assuming you’re the same anon). I had to seize the opportunity.
Someone asked a very similar question after it was posted and I answered here!
To sum it up, I think a part of Frostmourne’s presence lingered within them even after their freedom (as Barkentin pointed out, some NPCs hint at such), so I assumed they would have vaguely felt the severance from that. I don’t think they can explicitly tell anyone “there is a new Lich King and his name is Bolvar”, but their knowledge of the Scourge would probably tell them that something is still in control. They likely find this extremely frustrating.
Tevruden is always very careful to say ‘Arthas’ when he’s talking about the death of the Lich King. He doesn’t want to lie about the death of the lich king, but he at least knows Arthas got replaced. I assume that the Ebon Blade was sworn to secrecy about what they know about the fall of Arthas. Tev would probably say that he’s been ordered not to speak about it if ever questioned directly.