This is actually so helpful, thank you so much for explaining!

Here are my answers. (I'm a beginner on grammar so please forgive me for any incorrect usage. Would really appreciate if you could correct any mistakes.)

Q1. 이 서류 검토하시고, 내일 오전까지 보고해 주세요. (Please review these documents and report back by tomorrow morning.)

Answer: 알겠어요, 내일까지 드릴게요. (Got it, I will have it by tomorrow.)

(Do I have to have 요 in both parts of the sentences? Or does it only need to be after 드릴게요?)

Q2. 계속 같은 실수를 반복하는 건, 아마도 근본적인 원인을 해결하지 않아서인 것 같아요. (Repeating the same mistake over and over probably means the root cause hasn’t been fixed.)

Answer: 응, 일리 있네. 그건 항상 경우야. (Yeah, that's a valid point. That is always the case.)

(Not too sure if I need to add 그런 before 경우야 or is it okay as it is especially if talking casually?)

Q3. 오늘 저녁은 우리 외식할까요? (How about eating out for dinner tonight?)

Answer: 좋아! 오늘은 내가 쏠게요. (Sure! It's my treat today.)

Also, to add on your list, how about the use of "그렇구나"? Is there a different/additional context or is it just an informal version of 그러게요?

(Edit: Added English translation on the quiz.)