I am only using this plug-in to reward playtime points which they can use to purchases kits via the Kits plugin. I have no need for the /s so I would like to disable it if possible.

I would also like to disable /rewards because /reward is already a command on my server and it will confuse people.

You can change the command on the cs file to something else and solve it that way. 

For rewards you cold just disable all commands for the json