Noteboom(D31) Analysis-Verifying Schandorff

Here is a preliminary look at GM Schandorff's anti-Noteboom repertoire idea in Playing 1.d4 The Queen's Gambit 2nd Ed(Quality Chess 2012).

The first edition suggested the 8.Rb1 sideline but in the 2nd edition, Schandorff has presented a more positional idea in the main line-13.c5!?

I looked at Schandorff's proposed TN(21.d5!) and his other ideas. Now I'm happy I get the basics and this will have to do for now.

Lomineishvili,Maia (2401) - Melnikova,Yana (2171) [D31]
EU-ch (Women) 5th Dresden (2), 22.03.2004[Yip]
1.d4 d5 2.c4 e6 3.Nc3 c6 4.Nf3 dxc4 5.a4 Bb4 6.e3 b5 7.Bd2 a5 8.axb5 Bxc3 9.Bxc3 cxb5 10.b3 Bb7 11.bxc4 b4 12.Bb2 Nf6 13.c5 The idea is to play Bb5-a4 to blockade the queenside passed pawns (Diagram) 

Position 1
Black has just played 18...Ne4 to extend the light square blockade idea to the center.
Q1-What do think of black's idea?
Q2-How should white react?

White to Play