Bought a 250 quadracer hybrid. Im not sure about the axle if it is for a quadracer. I am going to sell it. It has yamaha hubs and rear wheels on it.

hard to tell from the pics, you might have to do a spline count on the end of the axle.
but some yamaha and honda hubs will fit them as long as spline count is the same, and for that
brake hub i never seen one like that before,

Do a spline count on both inner and outer splines, then measure the distance between the bearing surfaces and the diameter of bearing surface on axle.
Only way to really tell...