Not sure if your surgeon did your last endoscopy but if he didn't he will want to see your esophagus for himself before operating. They like to see the length of it.
None of my endoscopies have ever shown a hiatus Hernia but when the surgeon did my fundo, he said it was massive. Maybe your dude has a pretty funky scope.
Also, that swallowing test does sound like a barium swallow, it's not a bad test really. The stuff you drink is a bit chalky and I ended up with it all round my mouth!!!!
it can leave you a little bloated and constipated for a few days. When it does finally come out, it takes a while to flush! I'm in the UK and believe our toilets better than those over the pond so I not sure how it gets flushed there!
Don't worry about
them though, it's good that he's getting a very good idea of your anatomy before he operates.