Surely granulated sugar IS pure cane sugar....
I just bought a 25lb bag of granulated sugar, which is pure sugar.
If you are making your own HHB mix I would suggest (as a chemist, not a beekeeper, since I am also new!) that you make certain you use pure essential oils not synthetic ones as the synthetic ones tend to go "stale" sooner. Make sure they don't have additives either.
Not sure whether peppermint would replace spearmint and have the same effect - the chemical structure is not the same, but is similar. Not sure how critical that is.