Gamet is his traditional eye color. They look really awesome in, too. I have a pair I've been taking care of for a few years, and I love them.
The pink ones are awesome, though, I haven't seen those before. XD But they don't always change his color when he uses his power, and I think his black and red eyes are pretty much his signature look and what people will recognize.
Either of those wigs would work, depending on which version of the costume you're doing. Goodness knows he has tons and tons of designs. The first one seems like the hair he has with more of his variations, though. Except... Giving the version you linked another glance, the second one is probably closer (his hair is longer in that picture), but it would need to be tamed a little bit.