Playable, and even reasonable, but not easy, as it blocks the c-pawn.

White looks to be playing a Colle System - which, by the way, is an opening you might like to try. It does have a downside, but that is really among experts and masters, which you and I are not. Let me know if you want to find out more. I believe joe Karp knows something about it too.

6...Bg7 is tighter, and makes that triangle of pawns defensively quite strong. You don't really want to exchange that bishop off, neither, as it is your better piece at the moment (on account of so many pawns standing on light squares.

Wrong tactically, as it simply dumps a pawn. It could have been prepared by 7...a6. But Black had available a nice little attack with 7...Nb4, attacking the d3-bishop. If the bishop moved, to e2, say, then 8...Bf5 would have threatened 9...Nxc7 forking both rooks. The threat could easily have been stopped, but in making them, Black will have mobilised her pieces into active positions. Remember, threats - even easily averted ones - can be used as a means to an end.

Stops ...Nb5, but Bxb5 was called for. Now Black could shove the pawn to b4, forcing the bishop back, and tying up White's Q-side

Protects the b-pawn, at any rate.

Two attackes against b5. Defence by ...a6, or even ...c6 is now called for.

This could have waited upon protecting the b-pawn.

A very strong central break. Also strong were 10.Bxb5 and even 10.Ne5, with the same idea more or less as the text. Black is in a bit of strife right now...

The right response. To allow the pawn to advance to e5 would have placed a horrible crimp in Black's game.