Nee on it's own doesn't mean sister, it has to be "onee san" お姉さん or "neesan" 姉さん or even "Nee chan" 姉ちゃん. The plain type form of sister is "ane" 姉, and it only works with older sistersNee means sister Ne signifies something along the lines of a confirmation or agreement with something.
It's "sou desu ne" そうですね, the "o" sounds is elongatedSo desu ne = That's right (As you already know)
Baka is a noun and a "na" adjective, meaning that you have to put "na" after baka and before a noun like "baka na gakusei" 馬鹿な学生 or "stupid student"That's a noun. Bakabakashi means stupid and bakabakadeshii means stupid, and I believe it's an adjective.
Actually, suki 好き is a noun and also a "na" adjective, it's not a verb(Actualy suki means more of a like, and it's a verb, but if you're telling someone you love them, you can say suki da yo and such..)
