Speaking of Papa, from his discord he still thinks the Mallow/Smithy initial text leak may still be legit since the person has connections, but gets good and bad info. So it STILL can be true, at least that leak since it did get Rocket Grunt and Goemon correct, with the Grunt being the most random to even try to predict. (granted, I still am holding on to a large grain of salt since it is still a text leak.)
That's honestly been my exact line of thinking, as well. Right now, I'm really curious to see if Papa, Sabi, or someone else can contact the guy who made that Mii Costume list and ask them about what actually is going on here between that costume leak and the fake Terry one (whether they both come from the same source, whether one is leak bait and the other isn't, etc.).
Because to me, although my line of reasoning may be faulty on this, the CacoMallow hat leak relies heavily on the Mii Costume leak since Mallow was the key character in each. To me, if that Mii Costume list was actually fake but just a really lucky guess or something, I'd be hard-pressed to believe that some crazy dedicated guy truly did sort of piggyback off it and manage to create that difficult-to-fake CacoMallow leak.
However, if the original Mii Costume leak truly is real but this Terry one wasn't for some reason, I'd be more inclined to believe that the CacoMallow leak actually is authentic and that the Mallow hat is evidence to support it.
It just seems far too strange of a coincidence to me that within 1-3 months apart, two random credible Mallow leaks appear, unless they're either both fake or both real. That's why I'm really curious for some answers from the person with the Mii Costume leak.