I like to play Bb5 immediately to remove the important sicilian knight, many GMs recommend this type of idea to undermine black's shot at the center. I remember reading it in a Yermolinsky book at Nationals...

Still leaves e5 a nice target square which is somewhat awkward for black to defend immediatley especially because of the early c5...

After 4...a6, white is better off either transposing to a Kan with 5.d4, or bailing out into a closed Sicilian with 5.g3 d5 6.d3, intending e5/Bg2/O-O etc.

7.O-O is too passive. 7.d4 is indicated here.

This sort of puts a question to your d pawn though...

White needs to play d4 to challenge the center, as black will otherwise gain a big space advantage.

Giving black an isolated d pawn, which comes with space, but at this point with white's tempi and small development lead it should prove a target for the white pieces.

Good consolidation

yea, this move deserves a ? I think. g6 really rips open lines for those nicely placed rooks and the counterplay on the c file should prove too slow, this wastes a tempo I think... don't know the plan here honestly

Black still has a vulnerable back rank at this point, which could lead to tactics, I think white still has the advantage here, as even though the d pawn is isolated, it is also a passed pawn to boot.

Gives black the tempo back, I see potential for a hook and latter trick, but it just isn't there. g6 still had some interest and forced black to make the capture