Probably unlikely, but I would love to see Altaansar make it to the game. The idea of a CW that spent thousands of years in the EoT is really cool, and having it be to home to Maugan-Ra just makes it that much cooler. But the main 5 are an obvious must, however since only four SM chapters have been confirmed, if we had to have only 4 CW I think the Alaitoc might be the first one to go, simply because sneaking and pathfinders aren't as prominent a feature as those of other CWs and are likely gameplay elements not making it in at first, as I think I recall reading confirmation on no sneaking mechanics at launch of the game.
I personally think that Iyanden is first to go, having focus on wraith constructs, considering they will likely cost resources is just silly.
There's only really one classic Eldar colour scheme - Alaitoc. The other craftworlds are just variations/specialisations on the Alaitoc theme. I just hope the classes include Swooping Hawks and Howling Banshees. Forget Guardians, just use the Aspect Warrior types and have players later choose to either become an Exarch, die and become Wraithguard, show Psy potential and become a Farseer or run off to become a Harlequin. To bring the number of Aspect Warrior types down to five, just allow Eldar a gender choice and say that male melee = Striking Scorpion and female melee = Howling Banshee, with the other four aspects being for either gender. Leave out the weird spider web guys at launch and use them as an "7th aspect" expansion later.
I think you mis counted your aspects, I'm assuming "the other four" are dragons, avengers, hawks and reapers? That means you at least forgot shining spears just from the codex, along with crimson hunters and shadow spectres.
I didn't mis-count. I just don't count any new aspects that were added after 1997. If we're counting all the new-fangled additions after the core six then there's what...thirteen in the lore now? I can sort of live with Warp Spiders as an interesting addition, but all the others are just pilots of various kinds and Guardians can fill that role without having to dedicate an entire lifestyle to the task. The point of Aspect Warriors was supposed to be the type of armour handed down from generation to generation. You don't wear a bike or aeroplane.