Although not advertised as such (for what i could find), I recently learned The Mac Food Truck has gluten free fried seafood! The only item on their menu that isn't gluten free is their Po Boy, due to the bun. They can supposedly do your batter dairy free upon request.
I got the shrimp basket with fries and my mom had the fish basket with fries... and.... OH MY GOSH~ so tasty and no symptoms either!!
It had been so long since I'd had fried seafood!
Their Website: https://www.themactruckfoods.com/