4-3-2 crobat prime
4-2 ability cofagrigus
3-1 blissey prime
Pokemon Total = 31
Trainer/Supporter Total = 10
Energy total = 19
While your lines of pokemon work together, they take up way too much of the deck. You'll need more space for trainers and supporters to get this deck to work, so I'd suggest that you take out the blissey prime (if you'd like healing power, max potion is better). If you add in rare candy, we can greatly reduce your lines of crobat and chandelure. Both should be safe with a 3-1-2 line. Your cofagrigus should be fine at a 3-2 line, but I would make it the non-ability cofagrigus. The first attack allows you to move all the damage from one pokemon to one of your opponents. This should help out with the lack of blissey. You should only need one cleffa in the deck as well. This shoud leave enough room for trainers and supporters now.
With this reduction in the pokemon lines, you'll basically focus on crobat to poison and snipe quickly while you build up a chandelure on the bench. Cofagrigus is there for removing the damage from your own pokemon to put on your opponent. I would consider adding in jirachi as well since you can spread around damage with chandelure's ability and cofagrigus' attack. Jirachi can de-evolve your pokemon for quick knock outs.
With a little recovery, you should be able to greatly reduce your energy line. I would consider adding a few rescue energy (about 2) and reducing the psychic down to around 10 or less.
This is the area that needs the most work and should take up most of the deck. Maxing out your collector, increasing your number of communcation to 3-4 and adding in 3 rare candy will help you get set up quicker. The 3 PONT are great hand refreshers, but I would consider increasing it to 4. The supporter N will also help refresh your hand and possibly disrupt your opponent a little more. This deck is going to rely on you being able to switch out your pokemon easily, so adding in 2 switch and 4 junk arm to reuse those switch and any other trainer will help you do that. I'd also throw in a few catcher, possibly 2-3, to stall or get those knockouts. I doubt that you'll need the elm unless you're running up against a lot of trainer lock, so dropping them completely or going down to 1 should be safe. If you think that you'll need healing power as well as cofagrigus, a couple of max potion will effectively do that. The other trainer you'll need is a super rod to get energy and pokemon back into the deck.
If you have any more room in the deck, I'd consider adding in more draw power like cheren, juniper or sage. I'd try and stay away from judge and copycat since that could give you fairly low hand sizes when you need larger ones. This deck may often be behind, so you might want to add 2-3 twins to help you get caught back up.
With two stage 2 pokemon, your deck is going to be hard to set up. So adding in a twins line and well as significantly increasing your trainers and supporters, will help you get set up much faster. Once you're set up, you'll be able to deal and spread quite a bit of damage.