PS: If you REALLY want to use blue, maybe some blue floor tiles or ceramic tiles for the counter.

Don't put TOO much together in such a short period of time or the entire project may overwhelm you moreso.

I like the yellow. I'd say add red accents like a table cloth with a nice print (nautical, tropical, etc... whatever creams your twinkie). Add blue knick knacks such as maybe... picnicware or blue bowls...measuring cups...mix and match thrift store plates in blues..no major investing .. maybe a couple of seasonal prints you could rotate in and  out depending on your mood.

I'm all for jazzing it up, but for me there are limits as to how "busy" I'd want my kitchen to look. I like to have a hearty yet relaxing atmosphere and depending on my mood, the colorful accents come out. (such as the thrift store plates, glasses, etc). Plus if you go with the accents, maybe your son will enjoy picking out things with you. (How old is he anyway?)

As far as the self adhesive tiles, you could always do a plain pattern with them. (black/white or maybe just dark blues or a swirly blue... there is flooring available that looks like water drops but I don't recall where I saw that...)

The yellow color is very vibrant. I wouldn't put too much "jazz" into it. It's easier to add jazz a little at a time, than to take it away from a large overdone project. Colors affect moods (& vice versa. Red allegedly increases appetite, etc.). 

You may want to consider some "chalk board paint" in black preferably for notes with your family. And you can also cork part of a wall that could be a difficult paint job to cover imperfections. Plus it'd be handy for notes.

Good luck!