the 的 in 我的/你的/他的/她的 could be regarded as possessive pronoun of 我/你/他/她 and only in THIS case the 的 COULD be absent, while not in any circumstances, ONLY when .我的/你的/... is used in front of a person's title(e.g. mom/buddy/friend/teacher (妈/弟兄/朋友/老师), this person has a certain relationship with you, the closer the relationships are, the more likely you would take the 的 out! so it is a matter of casual usage vs. formal usage, you could say 我的母亲 which is pretty good in formal circumstances, and you could also say 我妈 which is casual and verbal, btw using a single 妈 instead of 妈妈 would make you sound more native, 妈妈/爸爸 would make you sound like little children, careful when addressing other people's mother, because 你妈 and 他妈 could be interpreted as strong swearing words when improperly placed...) . 我的/你的/... could also be possessive nouns like mine/yours/... in English. the 的 can NOT be absent. when used in the case as aaron的/中国人的/... the 的 serves as a possessive case(所有格) symbol, like 'von' in German and 's in English. the 的 can NOT be absent.

wow, that's a good question. I've never thought about that! even though I sing all the time. well, after analyze my singing (guess it seems quite silly if you could picture that...), it is really hard to tell if there is any tone in it, because I have to go with the melody with each character. So my conclusion would be you don't put tones in singing, just go along with the melody and rhymes. As to what to listen to, it depends on what genres you wanna dig. I am currently pretty into Jam Hsiao, a very talented and popular Taiwanese singer.

just like words spelled with latin letters, each character consist of several parts, get each part right and memorize them, then use the combination. well that's just my opinon