Well, first off, this is Easter coming this week for us the Orthodox, so I'll not be back before the second or third day of Easter. Also, the updates will not be very frequent, cause like I said I work on other mods too and announced it so someone else wouldn't get to it(and have to toss material I've made, like in the case of DUNE).
I don't have much to say, it's still early, but some initial thoughts of mine were:
There will not be many races, up to 12 and that IF I can find material for them. The leaderheads are important. Also I can't mod something I have no experience in, but that's good, it leaves space for someone who disagree's with me in the way it will be done, to make a MOO 3 mod and we'll be all happy.
So far I'm certain I can do Human, Alkari, probably Bulrathi, Ellerian, Maybe Meklar, unsure of Silicoid and Psilon(though I love Psilons), will do Sakkra, hope to be able to do Klackon, might do Trillarians, have to do Mrrshan, Meklar hope to be able to do(haven't tested a model I have). Might do Antarrans, however I don't know. I might just do Orions instead and introduce a new look. Also Trillarians might be replaced by a sea civ(how many units can come out of Medusae-shaped creatures?), but the ambassador will prob be a Medussa guy. Might do one or two different from what we know, for flavour.
Since I don't have MOO 3 but did follow through the production stages, as I remember races had categories(like Human, Ellerians and Evon were all of the same sub-race I think). So I don't think all need be done and I might keep Icthytosian category as a Trilarian replacement. But thanks for the list anyway Tledge1!

Also Bjornlo and Pfeffersack, your thoughts will be considered as well.
Also, do not expect an imitation. Firstly I don't like to imitate things. Second I just can't and have to work with what materials I have. Ellerians f.ex. will not look like the ingame shots(And I hated the way Humans looked in 2). I might be able to do similar models, or clothes, but I obviously can't promise anything on it.- plus I want it to have it's own character. I loved the ambassador screen and a version of it will be present. also the MOO2 emblems probably. On imitating, remember that even old Microprose's Civ2 MOO mod wasn't exact and had very few races. I expect to be able to do better(Or we will, if I'll choose others as co-members of the team).
The mod, might be mixed, like the Trek mod I'm working at, as in both ships and land units. Might be islands style(with space as water). Might be only land, as in a huge scenario that will see aerial units, MOO2 style. Might see the evolvement of all races from ancient years to the space age and beyond but I doubt it(too great scope and effort-time).
Personally i loved all MOO games I played, I like micromanaging, as it gave the game more life(as in having to trouble yourself like a RL emperor that cared would) and can't see real differences between the first 3 versions.
For those that haven't played MOO 0 it's a lot like ver1. I'll post a link if i'll be able to find it(it's a free dload), but remind me.
Barbarians might not exist, or they might be Orions or Antarrans(unsure about the Antarran look. They were too borgish, but I might go with that anyway to avoid extra work)
I did play one or two games of MOO 3 in a net Cafe, but didn't really like the graphics and feel. Micromanaging wouldn't be a huge problem. If you think it had strong points that could be used, post some pics, as a pic equals a thousand words. But buildings and stuff will come from ver2, unless you can impress me with something.
Also, if you have some thoughts or artwork, feel free to post. I can't tell you it will be included, but then again, it might. If you want something more included than the initial thoughts(like more races), you'll have to provide me with materials, definitelly(e.g. leaderheads. It's easy to do humanoids, but aliens for a crappy modeler like me, it's a nightmare).
Temp title for now is:
Master of Orion-Nightfall
(Homage to an Asimov novel and since my initial thought was a use of a weapon that would lead all races to forcibly rediscover all their techs, that will be probably be dropped as an idea, though I wanted to interfere with how all those races came to be)
That's my initial thoughts. Feel free to comment, but know I might not choose your ideas over mine, so don't feel bad if I don't. You can't satisfy everyone and I'm not aiming for it, as i'm not a game developer to profit from this.