Absol has actually fairly good stats, approaching the excellence when Mega-Evolved. It has a great movepool, allowing mixed sets with Fire Blast, Megahorn, Thunderbolt and Sucker Punch and may other options, like Ice Beam, Psycho Cut and Superpower but what's really captivating is the Mega-Absol: Magic Bounce. It bounces back Leech Seed, Spikes, Toxic Spikes, Stealth Rock, Thunder wave, Toxic, Will-O-Wisp... to the foe. Good, uh ? Excellent, not only decent. The main issue is the speed, but a speed-favoring nature must arrange it.
Houndoom is definitively your choice with Mega-Charizard Y because of moves like SolarBeam and Flamethrower. It has fairly good stats and the best speed out of the three, with the best special attack. It has an OK movepool and it may take Fire hits because 3 Pokémon of your team are weak to Fire, with Flash Fire.
Krookodile is a physical sweeper with Outrage, Earthquake and Crunch + Moxie. If you want a super sweepy team, he's your choice. Actually, I would say it has a rather good movepool with nice abilities.
I would definitively go for Houndoom without Houndoomnite and Flash Fire to tank Fire hits which screw easily your team. Hope I helped !