1)
Why does it say here "Yera'eh" and in Tehilim 18:11, "Yid'eh"?
1.
Radak: These are similar. 1
1
Here the verse emphasizes being seen, and there it emphasizes flying rapidly. (PF)
2)
Why does it say that Hashem appeared on the wind?
1.
Malbim (Tehilim 18:11): Two of the four 'elements' (earth and fire) deep in the ground were prepared to swallow and destroy. Hashem saved through the other two elements; the wind brought clouds (verse 12) to extinguish the fire via water.