Invalid takedowns don’t open you up to anything. The only risk to takedowns is misrepresenting the purported owner but that’s not the case here and the risk would be from Funko not Itch.
Much of the reason for DMCA abuse is that beyond the notice being assumed legitimate there is basically no risk to the complaining party until they dispute a counter-notification.
Not that this is relevant in this case, as it was not a DMCA takedown. A takedown notice would have been addressed to Itch.
At the very least what happened here is lying in a commercial context. Arguably something that should be illegal, and sometimes is illegal under the banner of "fraud". Again, the definition of fraud is not obvious (despite them arguing it is super explicit in the laws) and we have to rely on the lawyer priesthood to determine what the "sacred texts" say about it. Maybe even rolling some conjured up lawyer-dice and seeing what the Oracle at the Court says about it after they convene a little "ritual" known as a court meeting or deposition.