Electric/Poison
Psychic
I'm unhappy that Normal/Ghost was not put on the slate, despite its decent public support, but I guess the TL chooses the slate.
Electric/Poison is a intriquing typing that looks easier to balance than some of the others.
Pure Psychic is an interesting typing for this CAP, since it's weak to both U-Turn and Pursuit. However, I think that in itself makes it a good typing for this mon.
I am strongly against a Dragon type for this CAP, because Dragon is already an incredibly powerful STAB and I'm afraid it'll just end up as Draco Meteor/HP Fire/coverage/Shell Smash.
I seriously dislike Grass/Ghost as well. Grass has terrible offensive coverage and has 4 weaknesses...on its own. When it combines with Ghost, it gains another weakness, putting it at 5 2x weaknesses. With that in mind, I cannot in good conscience recommend a typing with 5 weaknesses and bad coverage for a bulky attacker mold.