Hw 5800pir

Is there any reason one would not want to enable lookdown monitoring on this sensor?

The look down option is provided as an added benefit but the look down function would essentially negate pet immunity, especially if placed over a doorway.

if i have the sensor enrolled at the panel with loop 2 (high sensitivity), does this verify that the sensor is in fact monitoring at high sensitivity?

Yes. Per manufacturer instruction, set the Loop to 2.