Can anyone tell me who is person in the shaded green?

I think it's Eirin.

I think so too, based on the shape of the hat (which...looks a little similar to Meiling's as well, now that I think of it, but Eirin was my first thought).

No.......Don't put my youkai savior into the old hag Deva

There's no turning back now, I'm afraid.

And... Who's the person in blue?

Gah! said:
And... Who's the person in blue?

Yuyuko, it seems.

I'm pretty sure that's Yuyuko due to the fan.

Green one has to be Eirin though.

Old ladies

Garash said:
Old ladies

I fear that's how the artist explain to me a while ago... *gasp*

Minase said:

Can anyone tell me who is person in the shaded green?

Eirin, definitely Eirin.