Also not a VGC player, but as far as I'm aware of, Amoonguss is the only one of these three pokemon that are really used in VGC, and it runs a different set than the one you have listed. If you want to use this core, I'd advise using it in the OU tier since it would work much better there than in VGC. If you're set on making a VGC team, I can't really help you there unfortuantely since, as I said above, I'm not a VGC player.