obtaining feasibility with a numerical tolerance of 10^-16 is just not a realistic expectation.
the best you can do if this is a must is to explicitly solve the equalities, and then work with the reduced basis, i.e if you have x and y and x+y==1, you derive the solution x=1-y and replace in the model, or alternatively [x,y]=[0.5,0.5]+[1,-1]z, i.e. symbolically compute the nullspace H and a feasible solution and write x as Hz+x0 for a new variable z