1)
Why did the Cloud stand at the entrance of the Ohel Mo'ed?
1.
Ramban #1 (citing the Ibn Ezra): The Shechinah itself wa inside the Ohel Mo'ed, and the cloud by the entrance.
2.
Ramban #2: The Shechinah, together with the cloud, stood at the entrance of the Ohel Mo'ed, since the Shechinah intended to speak to Yehoshua, who, unlike Moshe, was not permitted to enter the Ohel Mo'ed. 1
1
See Ramban.