Yes, I first encountered this Variation of the Modern Alekhine at Lewisham Chess Club. I always play 6) c4, as this limits Black to two plausible possibilities ... Nb6 (ostensible Mainline) and ...Nc7, I think that ...Nb4 can be easily refuted by  7) a3.

I am in the process of analyzing the Mid-Game for these Sub-Variations, thus far 6) c6. Nc7 leads to 7) Nc3. dxe 8) Nxe (quite strong for White, Castling can then be delayed once the Bg4 threat has petered out!). However, 6) c4. Nb6 is trickier and White must Castle at move 7 leading to 7) O-O. dxe 8) dxe (Mainline). This Line (as the Computer plays it) gets very complex but I believe that White can just about maintain an edge by the late Mid-Game.

good for white

I don't know about this one...I don't think the gentleman on g8 approves of this move.

White could keeping attacking blacks knight while developing at the same time.

give that a go next game yep mmmhhhmm

Nice!!!!!

I like it. I shall give it a try.