I found another solution for the placeholders - using the 2-step limited range move found in Dai Shogi. With this, I gave the new pieces new moves and tweaked some names and moves a bit, and problem solved. I also finished the first draft for the promotions. The only thing I am not sure about is the usefulness of the hit-and-run ability. A diagram of the new version has been added below. You may need to view this comment by itself for it to show.
I found another solution for the placeholders - using the 2-step limited range move found in Dai Shogi. With this, I gave the new pieces new moves and tweaked some names and moves a bit, and problem solved. I also finished the first draft for the promotions. The only thing I am not sure about is the usefulness of the hit-and-run ability. A diagram of the new version has been added below. You may need to view this comment by itself for it to show.