If an Adventure spell leaves the stack in any way other than resolving (most likely by being countered or by failing to resolve because its targets have all become illegal), that card won't be exiled and the spell's controller won't be able to cast it as a permanent later
There are many ways to check for counterfeiting on the market (differences in printed color, examining the print with a magnifying glass, difference in weight, passing through strong light, bending test, 5
Its a complicated process indeed, as we see, and its fun in a full-circle kind of way that the first card to make a token uses the word create just as weve done since 2016s Kaladesh
But when it comes to interacting with the other mice, it honestly feels lacking, especially for a type that is iconically synergistic, with so many cards designed to interact with each other and dependent on teamwork