I mean, no way whatsoever, you can just about get away with 3 cories OR khulis but thats it. You already have fish that stress the betta out, adding more will overstock the tank a lot and stress the betta out more.
I agree, and the shark will just nip the tail of the betta, and you shouldn't even consider shark if you don't have a very large tank, as to many fish keepers won't to keep them without researching and end up putting them in very small tanks which is unfair on the fish.
Don't add the corys till the tank has cycled as they are very sensitive to water quality, always be patient this way the hobby is enjoyable and not distressing, as a good fish keeper has to have patience to wait and no when to add new fish to a tank.
I know, but better to tell him forcibly than let someone else who hasn't kept up to date with the trolling give him the OK he's after But from now on I'll get people not to feed the troll... *goes to add some words to the animation*