Compared to the Kaisers, they're really low priority since you already have a copy.
The only time you should consider getting extra copies of event eidos is once you get all 6 free Kaisers, and that's 60k points, equating to quite a ridiculous amount of time spent before you actually need to worry about it.
Then again, you do have 3 copies of Icarus, so it's kinda up to you whether you want to set yourself back 1500 orbs to get a short term boost in Icarus. My take on that is it's not worth it.
I don't think they do, but I'm kinda hoping Kaisers refresh