"From W2 of defrost control to switch" Is this wired to the top of switch?
"From switch to heat element terminal in air handler" Is this wired to the bottom of switch?
Would the wire from the defrost control board be considered the power source?
W2 from defrost control is what turns on the aux heat during a defrost call. All you need to do is find that wire, cut it and put one side to the top and the other side to the bottom. You are making it seem more difficult than it is.