Simple,when creating a new Tau character we get the choice of either being a Tau or a Kroot.Also Tau CAN have melee,just not dedicated melee units that are Tau.
No, they think that meele is below them so tau themselves don't use meele. THEY LITTRALLY CAN'T FIGHT IN MEELE!
No,they dont use melee weapons,but im pretty sure that if a Nid is in their face they can use the butt of their rifles,like a hunter that gets pounced on.
Wincent is more or less right, I read the fight between Tau and Ultramarines on Pavonis (Novel name Courage and Honour). The Tau always kept distance while the Kroot went melee only. That is how the Tau work, you can see that even in Dawn of War best example being the Commander Unit (Shas O'? I am not so good with the Tau names though I really like the faction, shame over me!) He didn't even had melee attack or melee moves instead he jumped up and shot around on the floor. Though I also agree with Fino that in case an Assault Marine, Eldar Banshee, Ork Boy or any other kind of melee unit (Nids especially) that they would ram their rifle into them or kick them away or punch them in the face. But to sum it up: It will be up to the developers and most likely it will be equivalent to Table-Top Rules After all the developers are (what is good) pretty close to the Table-Top Rules / Codex when it comes to making this game.
Tau "can" melee, but they don't have any melee weapons besides their default Close Combat Weapon (read: the ass-end of your rifle). Their low S and WS scores, T3 models, and 4+ armor save combine to mean that while strictly speaking Tau "can" make melee attacks, doing so against any other faction is tantamount to suicide. Basically, they melee about as well as stock Guardsmen who didn't bother to take any power weapons, grenades (though in 5e all Guardsmen get frags stock), banners, priests, or Commissars. But yeah, they'll need Kroot if they want an actual dedicated melee unit, just like the Imperial Guard needs Ogryns.
the dark elder should just be another faction they add on later .. just my opinion, seeing as the Eldar are in the game all they would have to do is re-skin them
Can I insert a race, it does not have to be in at lunch but it would be nice if the considered it How about the Squats (if you remember them than your in my book of awesome) (and yes I am aware of them being 99.9 killed off, they could be a pay to play race, just my 2 cents)