It's normal for them to come out for food and a wee. Apollo probably does it more often than you notice
Also a change in behaviour might be because of the fireworks. Hammies do get affected by them and they tend to stay in their nest more.
The chattering is like you say, a sign that they don't want to come out and is normal too. There are times when I'm adding to my hammy's food bowl and he's in his nest, he'll chatter. It's a bit ungrateful of him but it's just a warning to say 'Don't think I can't see you touching my things.'