I think Large works well as the "big lizard."
I'm happy with the proposed HD and Con. I'd say Str should be pretty good, Dex moderate. Int is oddly blank, but Cha should be good. OK, have to run...
All the Animal Lords have Exceptional (15-16) intelligence in the original MCs, so I'd just give it the same mental stats bonuses as "Hawk Lady", although I might give or take a point for the sake of colour. i.e. Int 18-19, Wis 18-19, Cha 24-25.