You're an awesome father and those costumes are simply incredible. I can't wait until I can make costumes for my boy, Jack...but he's only a month-old The real Halloween fun with my son won't happen for years! The most I can do for him this Halloween is help my wife make him a garden gnome costume (I'm on hat and beard duty).
Maybe. I found with the Halo costumes that they still fit even after a year had passed. His Batman costume fit close to 1 1/2 years after I made it. Granted, the costume was spandex, so it did stretch. With that said, I don't mind. I love making them and they love wearing them (for now, although I suspect that this may change when they reach their teen years). The fact that they grow out of them only means that I get to make another costume. :lol
The chest does light up. The chest light is lit with a tap light.
The eyes light up too. I created the eye holes using velocro. During the day, when we attend our school parade, I intend on attaching a set of reflective plastic irriduim shields that I cut out from an old motorcycle visor. Glowing eyes would be useless in daylight and the reduced visibility isn't worth it. At night I intend to remove the irridium shields and attach EL lights using the velcro, so that the eyes will glow.
I am also working on the hands right now. They will have EL tape and will glow where the repulsor blast is supposed to come be.