I think it would be nice if you shared your method... just so others can avoid it.
I think rush jobs often end up being poorly done jobs. While I realize you didn't try to rush these hatchlings, I think it is not surprising that BPs that hatch earlier might have issues... and underdeveloped lungs would be one that makes a lot of sense. Lungs develop late compared to many organs, since they are not needed during the pregnancy/incubation period.
I highly suspect that the skewed sex ratio was just the odds gods having fun. I'm not aware of any evidence to suggest that any species of snake has gender determined by incubation temp or any of those types of methods. As far as I am aware, all species of snake have gender determined by sex chromosomes.
Thanks for sharing. It is interesting.