2K1b2n/2ppPk1P/R2PpPp1/6p1/1p4p1/1B4P1/3P3B/5R2 w - - 0 1
Well done! This is an example of a puzzle with the Pickaninny theme where a black pawn makes all four of its possible moves in the solution- 1 square forward, 2 squares forward, or capture to either side. In this case it was the black c-pawn in each of your four variations. When this occurs on the white side, it is called an Albino.
At last I have found how to get mate in 4 in all variations. I had difficulty with V-4.
1.Bg1 is incorrect.
I wanted to get mate in 4 in all variations but I couldn't do it.