There are six unlock steps listed on the Dev Wiki. 5 of them have been completed.

1) Does one have to go through all those steps before finalizing with the full unlock (when available)?

2) Does one have to go through all those steps even if I only need step 2, 4, and finally 6?

3) Can any of these steps be reverted?

Thanks!

May I suggest reading into the links on those "steps" to get a better idea of what they actually are. Then once you have basic grasp, search this forum and read some threads. You can also google some of those "steps" as well.

What you are calling "steps" are actually goals set out by the dev team. They accomplish all sorts of different tasks. What actual steps the unlock may require is not determined yet.

Enjoy your reading.