I feel like the three of these can be rolled together somewhat. How do you give dialogue emotion, have characters move without being stiff, and show depth and feeling in narration? By treating all three as the same problem. You want your writing to have flow and feeling, so you intermix the dialogue, the action, and the emotion.
Let's take an alternate look at your final example.
Amy's feet thump down the stairs as her stomach grumbles. She goes through the motions of preparing a plain bowl of cereal but then pauses, blinking into the fridge, taking five whole seconds to realize the milk is gone.
A crunch sounds from behind her, and she turns to look at her brother, who sits at the table with a bowl full of her cereal - and the milk carton. Swiftly she crosses the kitchen and snatches the carton, but it's near-weightless in her hand.
"Too slow," her brother mumbles past a mouthful of what should have been her breakfast. She bonks the carton against his head.
So what do we see here? Amy thumps down the stairs, hungry for breakfast. Does she get grumpy when she's hungry? The rest of the scene seems to support this. She's also tired - she prepares a bowl of plain cereal, the lowest-effort food she can manage, and she doesn't even notice immediately that the milk is gone. She doesn't care what's for breakfast as long as she can feed herself now. You see also that we skip the details of preparing a bowl of cereal. We all know how it goes, and making Amy seem too tired to care is a much better way of conveying the tedious familiarity of the act than describing its every motion.
The crunch, a comedic beat or a reminder of an unexpected situation? Amy expects there to be enough milk for her breakfast, suggesting her brother's presence wasn't planned for. He's a cherry of irritation on top of a bad morning sundae. Worse still, he has to rub it in with a taunt - referencing a habit of late mornings, perhaps, or a habit of lateness in general? Even just a tiny bit of dialogue can affect the pace of a scene, and reveal character in its delivery. It's an old taunt between siblings, and she responds in kind with a bonk on his head. A harmless bonk, since the milk carton's emptiness has been established with its lack of weight.
Does this help? Do you see how it's not only in what the characters do, but in how they do it? Not merely their actions, but their language and body language, the back-and-forth between them.
You also want to learn to vary your sentences. In each of the examples you give, I notice that almost every sentence plays out the same way. Read your paragraphs aloud, and try to notice when too many sentence are starting with a character name or a pronoun. Change it up a bit. Don't be afraid to sprinkle more adverbs in there, critics be damned, just as long as they don't fill up your sentences.
And read more. Study how the writers you like form their sentences and imbue them with feeling. Study how dialogue and action can be intertwined, or how one can be excluded for simplicity or emphasis.
And above all, don't stop writing. You'll improve with practice and time.