Punnet squares for eye color in aliens(2 genes)

[caters]

Here are the genotypes and corresponding eye colors and numbers in 100 of those:
Black(PPQQ): 7
Dark brown(PPQq): 15
Brown(PpQq): 30
Brownish green(PpQQ): 15
Purple(PPqq): 7
Gray(more like a blue-gray)(Ppqq): 9
Green(ppQQ): 1
Dark blue(ppQq): 11
Light blue(ppqq): 5

I try to do punnet squares for them and as it is 2 genes I can do a dihybrid cross. I notice though when I do the dihybrid cross it seems like I have 4 copies of 1 punnet square. Do I really need to do a Dihybrid cross for this or can I just do a monohybrid cross, that is for all possible combinations which is 9!(This is 9 factorial)? If I can just do a monohybrid cross that would be awesome but when I get to hair and skin color I would have to do a trihybrid or quadhybrid cross wouldn't I if skin color in this alien population has 3 genes and hair color has 4 and it doesn't matter which ones are dominant as long as a certain amount is dominant to produce a certain degree of purple color unlike us humans where it matters which of 64 combinations it is as to what the skin color is so is it right or wrong to do dihybrid cross for eye color since it is 2 genes?

Edited May 2, 2014 by caters