1)
What did Hashem mean when he appointed Moshe as Elokim over Aharon'?
1.
Rashi, Rashbam, Targum Onkelos and Targum Yonasan: Moshe will be ruler (and a judge - Rashbam) over Aharon, to issue commands which he will be obligated to obey.
2.
Seforno: That Aharon will perform wonders at the behest of Moshe.