The purple trousers have to go, but Lizzy should wear pants of some kind.
The lab coat can be on when Connors first starts to transform, but after a while the Lizard should tear off the coat.
Head shape should be lizard-like and not too much like a velociraptor or any other dino. Some lizards like the Komodo Dragon have forked tongues, but if Lizzy is supposed to speak at all, his tongue should not be thin and forked.
Five fingers and five toes on hands and feet, just like real lizards.
Tail should be about 5 feet long, and not too curvy. Only chameleons have prehensile tails.
Coloration can really be anything that looks good. Because of the Hulk, I wouldn't make Lizard a bright green. Either very dark green, black, gray, or even blue-grey scales could look good. Fade to lighter gray or cream color on the chest and belly.