Why did she say "stay" not "live", even though she's living in condominium?

Is "you know" in the middle of the sentence necessary?

No. Using "you know" is definitely not necessary for this sentence to be complete. Using "you know" in this type of sentence is just a way to fill space in the sentence. It gives the speaker time to collect his or her thoughts and figure out what she wants to say next. It is very common in English and you will hear them used in weird places that do not really make sense. Another example sentence would be: "You know, Annie, your plane is going to leave soon." Remember; this meaning isn't always the same for every sentence with the words "you know", but in this video, the above explanation is correct.

Would it change the meaning of the sentence if I say "pass by" instead of "pass under"?

Yes, it would change the meaning! Here, the words "by" and "under" function as directional differences. When you say "pass by", it usually means to the side or next to you. However, "pass under" refers directly to underneath you or an object. If perhaps, the river was next to them and they stood on the river bank, "pass by" would be appropriate. Since they are on a bridge that is over the river, "pass under" is used. Ex: Wait for the cars to pass by before you cross the road. Ex: Charles, can you pass the ball under the bench?

Why does he put "out" after "give"?

In this video, to "give out" something means to "hand out," or to "give something to another person," usually for free. When Dwight says "They don't give out black belts..." he is saying that black belts are not just given to anyone. They put the word "out" after the word "give" because they are emphasizing that things are being given to others for free. Ex: They are giving out free t-shirts. Keep in mind, "give out" doesn't always mean to give something away. It can also mean to come to an end or to stop working. It depends on the structure of the sentence. Just make sure to pay attention to the sentence. Ex: My knee gave out.

What does "bold" mean when it comes to the food?

Great question. I'd say that, when used in reference to food, "bold" means something like "strong", "daring", "overpowering". As you know a "bold" action can be more of risky or big action. Therefore a "bold" taste might be a somewhat unexpected and strong taste. It generally refers to a more strong or noticeable flavour. Ex: This wine has a very bold and fruity flavour. Ex: I find that dark roast coffee has a bolder taste.

Why would she kiss the egg? Is it a common gesture?

It was the chicken she kissed, not the egg. She kisses the chicken as a way of showing appreciation and love towards her. She is showing love to the chicken because the chicken laid a golden egg. This golden egg will make these farmers wealthy, which the farmers are excited about.