So many useless steps. And any delay in any step leads to harsh or rotten condition.
Ancient people didn't do all these steps, especially in places where water is rare.
This is the process that was used by russian northern (north-asian) tribes (eskimos, evenki, chukchi for example):
1. Drying (without deep cleaning, just removing blood and fat)
2. Softening (just placing skins or furs in many layers and walking on them)
3. Dry cleaning (more deeper than in step 1)
4. Tanning with whatever liquid substances.
5. Drying.
De-hairing process of deer skins was made with deer's litter. ;-) Without soaking, just washing and drying.
PS. Many methods of dry tanning includes smoking of inner side of furs.