This is a great topic. Thanks, Vlad, for posting about this. Maybe you will inspire more folks to see this fabulous film. I'd love to see it on the big screen some day.
The film version of NOTI has a *cartload* of differences from the original stage version by Tennessee Williams. The screenplay was adapted by John Huston and another writer. A copy of the screenplay was auctioned on eBay a while back, and I would have loved to have been able to read it--it would be interesting to know how the finished film differed from the script. Huston always shot his scenes in the order they were written, I believe he had a theory that this helped sustain the narrative mood for the actors. (my brain is barely functioning at the moment, so pardon my mangled English).
As for Grayson's stage training, she had been acting all over the Northeast for over twenty years on various stages, and had done two films (both of which she subsequently deleted from her "official" filmography) before her appearance in Iguana. She'd also done a fair amount of television, much of it now difficult to track down as she did small supporting roles that weren't well documented in published credits of 1950s drama anthology shows.
I've read a lot of the press coverage of the filming of Iguana, and it seems as if Grayson got along very well with nearly everyone. She managed the remarkable feat of making friends with both Richard Burton *and* Elizabeth Taylor. Elizabeth's daughter Liza became a friend of Grayson's son Matthew. One of my favorite anecdotes about her trip to Mexico was that she got this scopion venom antidote kit and insisted upon carrying it all around the country with her. I remember Matt mentioning at a Festival interview after she had passed over that that scorpion kit was STILL in the medicine cabinet at his parents' house.
Another bit worth mentioning is that Grayson had a bit part (basically a 2 minute scene) in an episode of Route 66 that was aired early in 1964. That episode was filmed in Florida and I've always wondered whether Grayson did it on her way home from Mexico.
G.