Don't hold your breath until any of this gets implemented, though. It is already possible to do these captures with the aid of additional scripting, as can be seen in the Ultima Diagram. Considering how extremely uncommon these pieces are, that seems good enough.
I don't know about "extremely uncommon," but they certainly are uncommon. I'm not asking for a rush on it, though; I just wanted to be sure that there wasn't a way of doing them that I was missing.
That said, using pp for "hops arbitrarily many" does have some appeal of its own, especially for certain large Shogi variants.
Short answer: Yes, that's correct.
I don't know about "extremely uncommon," but they certainly are uncommon. I'm not asking for a rush on it, though; I just wanted to be sure that there wasn't a way of doing them that I was missing.
That said, using pp for "hops arbitrarily many" does have some appeal of its own, especially for certain large Shogi variants.