Inside of beak looks good. No, he's not impressed LOL
Waking up to Almost empty crops? Crops should be empty/flat first thing in the morning before eating/drinking. Crop issues can cause some coughing/snicking - I would re-check again in the morning, if not empty, then I would begin...
Look inside his beak for any obstruction, canker or lesions.
Check his crop first thing in the morning to make sure it's empty.
Change in feed can often cause poop have a different appearance. I would just keep watch on that for a few days.
How much ventilation does your coop have? Photos?