1.Nc3 d5 2.e4 d4 3.Ne2 e5 4.Ng3 Be6 is given in "Smerdon's Scandinavian" and advocated as good for Black. However his analysis is not entirely convincing in the 5.c3! line (his 5...a6 is actually a fine move, but from there on something is missing).
But anyway, this is of academic interest: 2...dxe4 3.Nxe4 and now 3...Nf6, 3...Bf5 and 3...Nd7 are all fine for Black- I do not see why he should bother playing ...c6 and entering a normal Caro.
What are the independent characteristics of the Dunst/van Geet?
How is the Herrström Gambit independent, but the ECO A00 Dunst/Van Geet opening is not independent. The independent characteristics of the Dunst opening is that it allows black to steer the game into any number of positions. Heck, black could play 1 Nc3 b5. If white is willing to play 1 Nc3 d5 2 e4 d4, then thats a unique opening position.