Nami, are your web-comic "Another piece of candy" and "Treat" games canonical for the universe of "Syrup and the Ultimate Sweet"?
treat games are canon for this universe, another piece of candy is its own canon because i have more freedom that way.
Earlier in comments you said that all endings are canon. Did you mean all GOOD endings? Because if "Treat" games are canon then bad endings (for example, "Candibal") didn't really happen (we can see that Gumdrop is alive, Syrop is alive, Syrop still owns her shop, her shop still works and Pastila still works with Syrop). Thus making bad endings non-canon.