I like the block to block layout. In that case you can use the different yellows, I'd go one per block trying to keep roughly the same number of each of the fabrics -- so 2 or each or whatever.
I did a very similar quilt for a friend's baby, Ohio Stars (her hubby was from Ohio) many years ago. Had Winnie the Pooh fussy cut blocks, a yellow ring and then red blades, all set off with crisp white.