1)
Why here did they first fall on their faces and afterwards Hashem's honor appeared to them, whereas by Bil'am - in Balak, 24:4 the order is reversed, when it states "Machazeh Shakai Yechezeh, Nofel"!
1.
Moshav Zekenim: Because Bil'am was not worthy to see the Radiance of Hashem's glory. He had no strength to stand, and fell at the beginning of the vision, and did not see anything afterwards. When Moshe and Aharon sensed that the Radiance wanted to come, they immediately fell amidst Honor of the Shechinah, like slaves who bow to their masters, and afterwards greet them.