1)
Why does the Torah insert the phrase "Vayikrav Aharon el ha'Mizbe'ach"?
1.
Targum Yonasan: To teach us that, following Moshe's encouragement, Aharon overcame his fear and immediately approached the Mizbe'ach with Zerizus (alacrity).
2)
Seeing as the people's Chatas did not comprise an Eigel, why did the Torah need to add the words "Asher Lo"?