I have something minor I wanna add, along with some speculation.
We see in Snake's fighter video (or the E3 direct, I can't remember) that he has a new Dsmash similar to Zelda's, meaning his booby trapping abilities are nerfed without the landmines.
My speculation is that they will return as Snake's custom Down B. The landmines, while they can't stick to walls or objects, will detonate automatically on the nearest fighter, and will pack more punch.
Now I have proof that Custom Specials will return in Smash Ultimate. Palutena's set of Specials were streamlined to combine her Reflect with her Counter, but the moves I saw from the Miis would suggest that streamlining their Specials would be too awkward. We see the Brawler's Feint Jump in action, but in a photo, we see him using Head-On Assault; both Specials are his Down B. In the E3 presentation, we see the Swordfighter use both Blade Counter and Power Thrust -- both of which are Down B moves. And with the Gunner, we see her use Laser Blaze in the roster reveal, but later in the Direct, we see her use Charge Blast -- both are her Neutral B moves.
With all three examples that I just gave, it would be incredibly awkward to map these "alternate" Specials different to how they were in Smash 4, and to outright replace the Specials that are being mapped over.
....Okay, so maybe what I just said wasn't that minor.
