Is your yellowface female a single or double factor yellowface type II? Single factor YF II's have a yellow face and a seafoam green body, while double factor YF II's have a yellow face and sea green body colour that spreads as far as their upper chest.
So, if your female is a single factor yellowface type II and not split for recessive pied, the results would be:
25% sky blue single factor YF II dominant pied split for recessive pied
25% sky blue normal SF YF II split for r. pied
25% sky blue d. pied split for r. pied
25% sky blue split for r. pied
If your female is a double factor yellowface type II and not split for recessive pied, the results would be:
50% sky blue SF YF II d. pied split for r. pied
50% sky blue normal SF YF II split for r. pied
The study of genetics can be very complicated but it is very
interesting! You should look into it!
Co-dominance means that both traits shown together (like pied budgies and full body colour greywings).
Incomplete dominance means a blending of traits (like yellowface budgies when the yellow blends with blue to make green).
Semi-dominance refers to traits that are only expressed in the presence of other traits (like how violet factors work with dark factors).
Sex-linked means that the gene in question is carried on the X (or rather Z) chromosome (like opaline, cinnamon and albino).
Multiple alleles means that there are three or more forms of a gene for a trait (like with blood groups or greywing/clearwing/dilute budgies).
And then you get into more complicated stuff like pleiotropy, multifactorial inheritance, complementation, epistasis, expressivity, sex-influenced traits, sex-limited traits, conditional lethality, variance, penetrance and such and learn that although many genes seem to act in a simple dominant-recessive manner, they are way more complex (like yellowface genetics).
I hope I helped, good luck!