There is no point in step 4 (probably some confusion about the meaning of format), and at step 5, it won't clear the disk, it will rebuild it. Even an empty disk is rebuilt since it needs to be made in sync with parity again. If the disk has an empty filesystem, it will be rebuilt with an empty filesystem.
Another possibility would be, after step 3, New Config without the disk and rebuild parity. Then you would be protected again, and could proceed however you wanted with testing that disk, and later add it or a new disk (Unraid will clear added disk so parity is maintained).