You don't have to put command as !hdon (for example) you could use sm_hdon and still if peoples say !hdon on chat it'd work still. It would also guarantee your not replacing any other commands.
You should leave an observation after "- Install Metamod and Sourcemod on the server (easy)." saying "only if you haven't" because some peoples doesn't understand it and may think they have to reinstall.
You should also use infected_limit convar to limit common infected so server owners have more control about the limit.