And out of these three, two get WoW. I think Froslass misses it because she's the only Poke that evolves to be a ghost.
Acknowledged, but that does not mean that our Pokemon has to have Will-o-Wisp.
I see no law that says each and every Pokemon has to be as different as possible from each other. Infernape and Blaziken ftw.
Reversal and Baton Pass. Those two moves are comparable to Pain Split and Will-o-Wisp. I'm sorry, but Gamefreak did try to differentiate these two, it's just Blaziken was already meh and Infernape is just an all around amazing Pokemon.
And, plus, it's not like Will o' Wisp is going to be the thing that makes this a certifiable Dusknoir ripoff, plenty of things make this thing different as well. Most notably the seeming focus on offense over defense, if only a slight focus.
Incredibly slight focus. The focus on Offense equates to 5 more Base Attack and better STAB moves. Most proposed EV spreads so far have this Pokemon maxing its defenses much like Dusknoir. Will-o-Wisp will not make this a Dusknoir ripoff, but it comes very close. Adding Will-o-Wisp limits us in other, more widespread ways. I believe you would prefer the type coverage gained from the elemental punches over Will-o-Wisp, or maybe some recovery outside of Rest. I believe that sacking Will-o-Wisp is all we need to do to differentiate this from Dusknoir, and that's much easier than keeping Will-o-Wisp and limiting the rest of his movepool (like Shadow Sneak).