Nc3 is one of those aggressive and dangerous variations against the Dutch. I doubt that black has enough time to play b6 without getting in trouble. To my limited knowledge b6 is only feasible if white hasn't occupied the h1-a8 diagonal and if he can't force through e4 before black can set up his bishop on b7. 

Something like 1. d4 f5 2. c4 Nf6 3. Nc3 e6 4. e3 b6 5. Nf3

I've taken up the Dutch in the past few months and one of the things that bothers me is that, against White's various non-main-line variations, Black needs to be prepared with something different against each one.  One thing vs. 2. Nc3, one thing vs. 2. Bg5, etcetera.

A few days ago I drew a titled Italian master on chess.com at G/20 using the Nimzovich variation against the Staunton Gambit (1. d4 f5  2. e4 fxe4  3. Nc3 Nf6  4. Bg5 b6)  and this got me to thinking -- couldn't ...b6 likewise be used as a sort of system against other White lines involving an early Nc3 and/or Bg5, particularly on the second move?

Yesterday I played 2...b6 vs. 2. Nc3 and my opponent attempted an outright refutation: 3. e4 fxe4  4. Qh5+.  This however shouldn't yield much after 4...g6  5. Qe5 Nf6  6. Nxe4 (6. Nd5 Nc6  7. Nxf6+ Kf7) Bg7.  Or if 4. Nxe4 Nf6 (but not 4...Bb7??  5. Qh5+) -- I've determined the key for Black is, ironically, often delaying ...Bb7, for instance if now 5. Ng5 e6 first.

I realize there are many pitfalls for Black if White plays perfectly, for instance I've worked out the following line where Black seems to just barely be holding.  But still is there benefit to playing ...b6 as part of a system, even in the short term, just to become accustomed to handling these types of positions?  And/or maybe the immediate 2...b6 is more viable against 2. Bg5 though not necessarily against 2. Nc3, where perhaps it needs to be prepared with 2...Nf6 and if then 3. Bg5 b6!?

Thanks for your consideration