Also if you're going to make a whole gang of characters keep in mind to contrast them! if you do 5 pink cats with different colored eyes you will look very uncreative! and don't forget to do different animals as well!
ive found tht bright blue or bright green eyes work the best against dark colors. do u think thts good? my icon is an example someone made me. is the colors right? (i cant change but it would be helpful for any future refs. its a breed from a friend)
Any bright color works againts dark colors because you have one of the base contrasts at work which is dark light contrast. What hue of color however fits better together to make the design seem better is both subjective and a cause of other color theory contrasts. Like with your icon, the contrast would be even better if the canines fur were brown/red instead of brown/yellow since red and green are complimentary contrasts and you would get some warmth in there.