I just did a bit of search research. The heat sesnor seems to be for high temp ops generally associated with the A/C unit or high temp driving situations. In normal use the temp switch does not activate the electric fan. So for normal driving the belt driven fan will handle it. To answer my own question...strictly speaking the temp sensor switch is redundant and could be left unused with the caution that you don't have a back up fan for a high coolant temp situation.
I did manage to get the old sensor out with the use of penetrating oil. I then used a bit of silicon and a new seal when installing in the replacement rad.