Timeline theory
Anita and the fact she is with Snozzi on the subway does open a few ideas on the possible expanded universe of Cruikshank's works. Had Quasi's Cabaret been developed into a film it or Make Me Psychic would have been the earliest points to the timeline. Next comes Quasi at the Quackadero which has the ending of the titular Quasi being stuck in dinosaur times. Then comes Face Like a Frog due to Anita and Snozzi being passengers on the train along with implications Anita and Max must have met before. Finally comes the shorts with Anita and her friend Whinsey the horse where we learn at some point Anita got rid of Rollo and replaced him with a sentient car that runs on positive vibes known as a BARF.The singing lizard is Satan.
Because of the reveal that the basement leads to the subway to hell. The fact that the lizard appears again after the subway leaves adds to this. The reason why he tells Max not to go in the basement is either because he's a Noble Demon who genuinely wants to warn Max, or (more likely), it's more like a Reverse Psychology thing to get Max to go in so he can trap Max in hell. Danny Elfman, who voiced the lizard, also played Forbidden Zone's depiction of Satan 7 years earlier, who also wore a suit and had bright red hair, so this could easily work as an Actor Allusion.