>>33237126>The presumption is that the next 2 placeholders are for totem mimikyu/busted disguise totem.It's not a presumption. The PGL placeholders are labeled with a number which corresponds to that form's ID number in the game's coding.
>020-02 = Totem Raticate>778-02 = Totem Mimikyu (Disguised Form)>778-03 = Totem Mimikyu (Busted Form)>801-01 = Magearna (Original Color)>802-00 = MarshadowLycanroc's placeholder is the only one whose form ID doesn't correspond to an existing form. In fact it's three higher than any existing form, which implies there are two other forms unaccounted for (don't get excited, they're just Midday and Midnight Totems, you can clearly see the Midday Totem in the trailer).
Of course this doesn't necessarily mean Mimikyu won't get a new form, as none of the other USUM-exclusive forms have placeholders, only Dusk Lycanroc (it and the two Totems probably have placeholders because they were planned for SM but removed at some point). But people thinking it's guaranteed because of the placeholders are deluding themselves.
As for why the other Totems don't have them, they presumably did at some point and in true Game Freak fashion someone half-assed their removal. A similar thing happened with the Bank Pokedex sprites; there are unused sprites for most of the Totems, but not for Lurantis or Salazzle.