According to FGTV's Chapter 11 - Wilikin Factory. The villain stash is just like the Giant chest from SSF. I thought that villain stash was going to be way better than that. They're just basically getting rid of Giants and replacing it with villains.
this has been known since the first level play through video of soda springs.
Villain stash is a hoard of coins accessible only by villains, there is also villain quests, which are specific to an individual villain, the one or two i've seen, in rain fish riviera i think, seem to be similar to the elemental gate areas, though there hasn't been enough shown or said about them to see whether they are any more or any less.
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271figures+11Vehicles+55Traps(+Outlaw,Riot,Steamed,Rebel,Steampunk)+38Magic Items
TrapTeamNeeded:Life and Water Minis (s2)