Easter Eggers are merely chickens that have the blue egg gene. They could be from Ameraucanas, Araucanas, or from some of the other blue egg layers in South America. They may or may not have muffs or tufts, may be rumpless or have magnificent tails, may or may not have a pea comb, may have any leg color.
At least you have made progress. Now you know one thing that is not causing your problem. Good luck on finding what it is.
Its strange the I have a higher hatch rate with the pink eggs than the green? My EE/bantam cross eggs usually hatch better than my standard EE eggs too? Very strange? I've always said that the bigger the egg the lower the hatch rate (for me). Those tiny bantam eggs hatch like crazy with no problems! I just don't need any more bantams, I need more full sized hens!!