It depends on the species, season, and sometimes gender. But generally they could be brown, grey, or white.
brown and gray
All owls are covered with feathers of different colors.
Yes.
cookies
Hair? No. Feathers.
feathers
Young barn owls need feathers to keep them warm and for flight once strong enough.
tips of the main feathers
They don't - they have feathers
Most arboreal owls have feathers the colors and even the patterns of tree bark to camouflage them, and this protects them while they sleep both from predators and from harassment by prey species. So I would say "coloration" is their primary method of camouflage.
Owls have eye LIDS, but no eyebrows. Being birds, they do not have hair, but feathers.
Young barn owls need feathers to keep them warm and for flight once strong enough.