Single factor Yellow-faced type 1st: cream face & blue body.
Double factor Yellow-faced type 1st: same as skyblue budgie, cannot be tell from skyblue.
Single factor yellow-faced type 2nd: yellow face and both blue and bluish green body, called seagreen. Blue confined to belly and underside wing coverts.
Double factor yellow-faced type 2nd: yellow face and blue body. Body usualy entirely blue, but sometime have little green, etc seagreen on breast & rump.