Why does it list Amram and his wife, and not just write 'Mishpachas ha'Amrami'?
Ramban, Moshav Zekenim (57): Because his children were divided into two sections, Kohanim and Levi'im, and it is befitting to list Aharon and his sons independently.
Why does it add "asher Yaldah Osah l'Levi b'Mitzrayim"?
Rashi: To teach us that Levi's wife gave birth in Egypt
Ramban, Moshav Zekenim: Hashem held her back from giving birth earlier, because (she gave birth to the redeemers