We depicted Eol as an elf at Cuivienen who quickly got angry and left the great debate early in Season 2. So, he's definitely Avari in our adaptation, not Sindar. I am not sure if we made it clear if he were of the people of the Noldor or the Teleri to begin with. (We went back and forth on that, and since he's a bit of a loner, his affiliation might not be clear.) There were arguments for wanting him to be related to the Noldor (particularly the family of Míriel, who also become Avari), and this would come into play with his affinity with craftsmanship and dwarves, and the insults leveled against him by the sons of Fëanor. But then again, there were also reasons to want him to be a relative of Thingol (perhaps distantly, but still 'kin' in some sense), so initially Teleri. I'd have to go back and check the script outlines to see if any explicit choices were made there.
We did discuss having prehistoric creatures in Season 1. Haakon and I like the idea of the destruction of the Lamps corresponding roughly with the
K-T extinction event, though to be fair, that's not an official decision of the show. Oromë and Tulkas hunting down some of the beasts of horn and ivory *is* part of the show. We definitely were leaning towards extinct beasts there.
It was very important to me that we not show 'modern' flora and fauna in the earliest days of Almaren. I didn't want fields of grass and flowering plants and trees right off the bat - I wanted to show a gradual development of such things. The first flowers, bees, honey, and mead are all developed for Tulkas' wedding under the light of the Lamps.
For similar reasons, I do *not* want to show dinosaurs as contemporary with elves. It's one thing to establish that Morgoth might have kept some beasts in his menagerie that could later give rise to, say, dragons, or the steeds of the Nazgul in the 3rd Age, even (off screen, of course). It's another to have elves tangling with T-rexes. Let's...not. As for Ice Ages...obviously, those are much more modern, and one could argue for saber-toothed cats or mastodons co-existing with elves, if one wanted to.