Actually, the change to rule 1 is the one I feel least strongly about--you
make a good case and your way is simpler.
My contribution is not great enough to have a variant named for me--I'd
be comfortable with a thank you on the game page, if you insist.
On the no checkmate by Pawn drops, you may well be right also -- but this
may be less necessary with no drops in zone 4.
Personally, the one Shogi rule I have never liked or understood is why it
is legal to check the King with a Pawn drop, but not to mate. To me,
prohibiting both or neither would seem more logical.