My question is whether druids know about the first elves like Viridia. The Order of Maidens knows about the Shardmaiden, which is one of the first elves. The question is whether they do know about the others?
Looking things over a little bit, I'm not
sure the Order of Maidens know a lot specifically about the Shardmaiden, though I imagine they have impressions of her life and memories as they do portions of her magic. That's how I would play them, at least: they might have preternatural insights from the life of the Shardmaiden. The way I would let this play out is (in keeping with replies above) their memories of the others are hazy, but they may instinctively know when something they hear about one of the other legendary elves is false. Regardless of their level of knowledge, it likely comes from their particular shard or word-of-mouth from another Maiden.
Druids generally speaking? No, unless they knew one of the elves in life, and even then their memories of those times have likely faded. Let them use LORE and give them snippets for each success; as a possible explanation for the source of their knowledge, if it fits, say they learned it from a member of the Order.
Thanks for reclarifying the purpose of your question.