Basically, the best clue is whatever the egg color is when they start laying is the color you will get. I know that's not what you wanted to hear but it's easier to spell it out at the beginning. I bought an EE that was a sure blue egger (she said) but it lays lrg green eggs. Yeah, I was a little disappointed but we still love the green eggs. Bird color... again is no clue to egg color. One of my EE is orange and white and the other is a EE/ sussex mix (a lot bigger than the others) and she is white and black (just like a light brahma) they both lay the same shade of green egg although both eggs are different sizes.
Have you seen the posts regarding the meet up in Pomona on May 31st? Many keepers will be there and you can learn a lot talking to those crazy people. And it will be loads of fun! And you might find some good deals on chickens....