LOL! I'm guilty of also trying to trick my cats. My cat Tiger has become so smart that if he sees me mixing his wet food for even one second, he knows that I must have put meds in it and he starts walking away before I've even put the plate on the floor!!! I swear I can here him saying "forget it!". My latest trick was to mix all the cats wet food in front of him even though his is the only one with meds in it. The other cats just ended up with 'whipped' wet food with all that un-necessary stirring. It worked for a little while until he caught on.
Tiger is now getting his meds in a transderman gel so the trickery has stopped for now.

I have two suggestions that might help.
What if you put a full bowl of kibbles inside a larger bowl that has water in it creating a 'moat' that the ants won't cross. If you put this double bowl set up farther away from his litter box, he will hopefully have the litterbox scratchies over and done with by the time he gets to the new location of his dry food. (or you could just move his dry food to a new location without the moat and it would probably work too. Being near the litterbox, things are liable to get knocked over while he's in scratching mode).

The other idea isn't nearly as fun as a moat but if you switch him over from being a free feeder to giving him his kibbles as meals he'll probably start to get excited about the smaller portions because he will have gone for a period of time with no crunchies. He might not be amused with this type of plan though!