They all do help in the war. The elcor help out when you save their home planet I think. Bavarians help if you get the extra quest in mass effect 1 where you decide between killing a Batarian terrorist or saving innocent lives. In ME3 you get decide to kill or persuade. Persuasion leads to his assistance.

Vorcha come along with one of the mercenary groups. Volus I think you do a certain quest. But yeah, all races can help.

So Anima :D.....

But I think she just forgot. She did have to rewrite everything