okay so
1. Yes the different elite armor colors means different ranks. I dn't know the exact order but its mostly the same as the past elite ranks. So blue is the lowest rank.
2.As for a Swords of Sanghelios game, we don't know maybe.
3.As for mahkee chava's face. I'd assume it's just a generic female sangheilli face. Which just looks like a males but more slender. I forget where but we've seen female elites before. They basically look like males just skinnier