The only co-habitation setups I agree with are ones focused around animals that live in the same locale. For example, ribbon snakes and green anoles. You went and mixed 3 different animals from 3 different countries...Then tried for a 4th....
And from the sounds of it you also went and put a wild caught snake in with 2 captive breds? You mention quarantining him... but did you actually treat him for parasites he most likely has? Along with exposing them to the possible bacteria and all from the outdoor substrate...You even trying to put a pac-man frog in there is ridiculous because they will try to eat anything they can fit in their mouth, including the other snakes and the swift once they're large enough.
There is so much wrong with this experiment that honestly I'm pretty surprised you would post it knowing how so many people dislike this sort of thing.
It feels more like the people I would have to educate about reptiles at a big box shop with one cage wanting too many animals instead of an actual 'experiment'...