Pink, you have completely forgotten that we still have the ability and movepool to decide on. Looking at that list, I reckon with a combination of the two, CAP9 would be able to stop all of them and the only ones it would need Taunt to stop are Gravity, Trick Room, Taunt and Encore. Of course, CAP9 does have two ability syndrome so the list of moves its ability wouldn't stop would be longer depending on the chosen ability/ies.
By the way, we have not yet stopped Trick. Pursuit, contrary to what you have said, does not work wonders, but allows something else to come in and set up, be it DDMence, DDGyara, SDLuke, NPApe, SDScizor or whatever.
Also, if anything, Heatran would encourage Celebi to use Leech Seed, while CAP9 would encourage Celebi to attack directly; therefore the Celebi user would be in a bit of a dilemma.