Shell money began as commodity money according to most sources- shells were inherently valuable because of body ornamentation as you mention (similar to how gold was useful to easily work into soft metal jewelry).

If Chucky cheese tokens are money at all, they are “representative money” because they can be readily exchanged for various commodities by the issuer (the prizes and games).

A central authorities decree is not required for money to be fiat, it just simply can’t have intrinsic uses like commodity money or be directly redeemable for commodities like representative money. It has value purely because we have confidence it will have value in the future - and historically the most reliable way to do that is by government decree, but it could also be by a mass consensus that a particular crypto coin will still be used in the future.