For singles, I used a Mega Charizard Y, Garchomp and Rotom-W. I didn't have much difficulty as Rock types weren't common during my Singles run and neither were any Chlorophyll users. My main type would have to be to not use set-up sweepers (That are frail) as you don't know hat the AI will pull out of it's ***. From what I see in your team Chibi, Blaziken doesn't fit Battle Maison (Honestly, I can't even use the thing on Showdown). The best thing to do would be to run a fast and strong Mega as a lead (i.e. Charizard X/Y, Pinsir, Houndoom, Manectric, Absol or Lucario).
For Charizard X: on the first turn use Dragon Dance, the destroy using Flare Blitz and Dragon Claw, roosting off damage when necessary.
For Charizard Y: just hit with whatever's super-effective, but don't forget Roost. Do not be afraid to switch out if a threat is present.
For Pinsir: set-up with Swords Dance if possible, otherwise abuse Quick Attack, Return and Close Combat.
For Houndoom: try to lead with Sunny Day, the proceed to blow up everything with Fire Blast, Dark Pulse and Solar Beam.
For Manectric: same thing as MegaYzard, just hit for super-effective damage.
For Absol: this guy's a mixed sweeper in my eyes, being able to run a devastating Bolt/Beam, Rough Play, Sucker Punching set.
For Lucario: lead with either Nasty Plot or Swords Dance, going for absolute obliteration with this guy. The only thing that can stop a +2 Mega Luke is status and Banded Conkeldurr Mach Punches.
As with all Megas, status is their bane. Make sure you have a healer on your team that can switch-in to almost anything - such as Clefable, Chansey or Miltank - and use Aromatherapy or Heal Bell. Finally, make sure you have a second sweeper that excels in the area opposite of your Mega and pairs well with them (i.e. Mega Doom, Clefable and Tangrowth or Chlorophyll Leafeon). After that it's all luck.