Agree with all comments above. Here's some clarification.
Why is the canopy or cover important for choosing NV or Thermal? First, because NV uses moon light or star light to illuminate an animal. If an animal is standing in the shadow of a tree, hay stack, etc., it's not being illuminated by the starlight and you can't see the animal. Yes, there are shadows at night. Thermal detects the heat generated by animals, plants, buildings, etc. and does not need illumination from another source to see. So thermal is not affected by a canopy or shadows created by moonlight, etc.
Second, thermal can see through or around bushes, leaves on trees, etc. and NV can not. A covert flashlight/illuminator added to your rifle to supplement starlight will reflect too much light off closer objects like tree branches which blind NV just like approaching car headlights blind you while driving, so you can't see the animals.
Why use white or red lighting over a feeder? Because the animals get used to the light and continue to feed at night - even the deer. For a one time hunt, lighting over a feeder is much more cost effective for you because you can use a normal rifle scope, especially if it has an illuminated reticle. A light that remains on all night is better at not scaring animals than one that turns off and on numerous times during the night.