We checked the thermostat by spraying it with an inverted can of air and measured the resistance at .1 ohms. Is that too low?
No, it's not to low.
Original symptom was freezer not cold (food not frozen anymore) and a buildup of ice on the back right side of freezer.
Was ice built up pretty even over the evaporator or did it seem like it was just iced up in the corner were the two lines connect to the evaporator?
If it was just iced up in the one corner you maybe dealing with a sealed system problem, such as a restriction in the refrigeration line or low on refrigerant.
If the evaporator was iced up pretty evenly then I would say it sounds like your dealing with a defrost problem.
Did you manually defrost all the ice while you had it apart?
If it's iced up again could you post a photo of the evaporator for us to see.