Drieing can create matting in certain washing/drying machines. It's best to spread them out and let it dry by air. The high washing temperatures removes their natural grease-layer which makes them more matting/tangled/felty when tossed about after. Be sure to when still wet comb then in the shape you need before letting them be air-dryed.

Technically just high temp washing is enough health-wise. Animal hairs are low on the scale of spreading deceases etc. in itself. It is mainly for parasites/fungi that might live in it and can be spreadable to humans. And skinflakes that can trigger allergies in people.

Put them in a delicates washing bag and throw them in the washingmachine with soap on the highest (90 degrees celcius) program.

Depending on what animal hairs and amount of you might want to do it twice (sheep for example; curly hair).

Cleaning by hand unfortunately often results in matting/felt.

Yes.

The more moist your environment is; the thicker shelves needed.

Some woodtypes can be better at it, the not bending, like oak.

But it really depends on where you live. Your climate. Humidity.