Sounds like ammonia poisoning. Individual fish can have different responses. In a closed environment, like a bag of water traveling thousands of mile with a big waste producing fish in it, the stress level of each individual fish could produce more or less ammonia.
The temp acclimation w plop & drop method which was suggested by numerous folks when you asked about acclimation is the best way to avoid ammonia poisoning with fish that have travelled from half the earth away. The toxicity of ammonia is less at lower pH. When you expose the water to O2 the pH suddenly rises rapidly increasing the toxicity of ammonia.
Did you do the 5x dosing of prime? Prime does turn ammonia into ammonium until it can be cleared by a biofilter, but the best method is to remove the fish from an ammonia rich environment as quickly as possible.
Any change/increase in your tanks bioload could also result in nitrites in your water, even if undetectable on test, so I would add salt at 1tbsp/5gal to prevent nitrite poisoning.
Glad the other female is doing better. Unfortunately, as far as the male goes, this remains a watch and wait scenario now. He definitely looks better in the last pic. Keep the water pristine. Replace the salt w water changes for the next 2 weeks.
Keep us posted