It does sound like it could be barotrauma...especially in the yellow belly's case...considering the depth the fish came from...now fish have come from deeper I will admit but what also is a factor is to how quickly they came up.
With the bass I would say it could just be 'one of those things'...I have had fish in my livewell survive for hours without a problem...and yet have had same size fish from same place start to go downhill within a hour of being placed in the livewell.