Yes, you must return meta results and yes you need to worry about OVERRIDE and SUPERCEDE. The Metamod documentation says well how they are used. Please bare in mind that I upgraded the project file to VS 2015, I don't have older VS, so you will have to upgrade also.
I created a pull request with my changes. Please compile and test it out before accepting it. The bot can be used with or without Metamod now so everyone should be happy.
P.S. I upgraded the FakeClientCommand() function to more modern one used by most of the bots here, now you can use it as the original engine ClientCommand().
EDIT: I just fixed some nasty issue that I missed out. Pull again from the branch using the git pull --rebase command, because I amended the commit.