1)
Why did he say "Asher Amadti Lefanav"?
1.
Ralbag: (Eliyahu is Pinchas 1 .) Just like I killed Zimri, and did not fear all of Shevet Shimon, for I was in front of Hashem, also now I will appear to Achav. I do not fear him, for just like Hashem saved me then, He will save me now, for I am still in front of Him!
1
Refer to Shoftim 20:28:1:1 and the notes there.