When something smells good, we usually use 향기. 냄새 means every smells including both good and bad things. So we don't use like 지독한 향기(X)ㅡ지독한 냄새(O). 향 is almost same as 향기, but most people use 향 on a liquid, not 향기 I think.

Your mistake is much smaller than my mistake that I'll make when I learn French. I'm not good at English so I add Korean too.. 내가 프랑스어를 배우면서 할 실수가 님이 방금 하신 실수보다 훨씬 많을 거에요 = 그 실수는 별 것도 아니니 신경쓰지 마세요

지금 오빠가 교통사고 때문에 서울을 떠날 수 없다는 게 사실이에요?

They're almost same words, but each term has kind of different meaning. When you want to stress something is for selling, you should use 상품. However when you want to stress something means an article(object? or stuff) more than selling, then you should say 제품. I'm not good at English..But I hope you'll understand.

뿌듯하다 - the feeling that you can feel by yourself after you did nice job 자랑스럽다 - kind of 'be proud of'..?(it doesn't matter whether you did or other people did) I'm not good at writing in English.. but hope you'd understand.