Hi Kathy,
1) Not, it is not necessary - as long as you have at least ony folder with the correct .kf and refer to it in the artDefines.xml (and you should have an artillery.nif in the same folder)
2 and 3) In this case, it was quite easy, but it has been a long time ago, and I do not remember everything. I just altered artillery_md_run.kf
To turn the whole unit, I edited "1 NiTransformInterpolator", because this was linked to "Dummy_Artillery_Body" (every item which has to be turned needs to be linked to this node in the nif - linked to MD oder MD_NonAccum only would to rotate the unit in this case). Whithin this TransformInterpolator I set "Rotation" to R =-180 for a horizontal turn.
In "0 NiControllerSequence" you can find the "NiTransformInterpolator" linked to each Bone within the different "Controlled Blocks" blocks.
I do not know enough to write a tutorial, because I only did this for the Artilleries and Horse Artilleries with just one node.