I am a little bit confused but it seems like your hair is thinning at the very front and in the back?

You can order a hairpiece in any size or shape you want. Your sides seem to be good so I don't see any reason why you couldn't order a piece in the shape of a mohawk. The two problem areas with full caps are the nape and temples so if You are able to keep your own temples then half the battle is won. The only challenge you might face is the blending in the back, since the blend area is going run parallel to your growing hair, as opposed to overlapping it as a regular partial would.