I feel like the bosses in this generation are easier to get to, but slightly harder to beat depending on if the game wants to end your streak at 50.
I've gotten all of the trophies (except for Super Multi, granted that using an AI trainer as your partner to get to 50 is probably similar to performing heart surgery on yourself) using mostly the same Pokemon for all the different supers. I guess I'm sort of lucky, since I only lost once in each format somewhere between Battles 35-50 before getting to the bosses.
I did all the formats using some variants of the following 6 Pokemon:
Kangaskhan @ Kangaskhanite
Ability: Scrappy / Parental Bond
252 Atk / 252 Speed / 4 HP
X/31/31/31/x/31
Jolly Nature
- Return
- Earthquake
- Sucker Punch
- Power-Up Punch
Talonflame @ Sitrus Berry
Ability: Gale Wings
124 HP / 252 Atk / 132 Speed
31/31/X/X/31/31
Adamant Nature
- Brave Bird
- Flare Blitz
- Swords Dance
- Tailwind
Greninja @ Life Orb
Ability: Protean
252 Sp. Atk / 252 Speed / 4 Atk
X/X/X/31/X/31
Naive Nature
- Surf
- Ice Beam
- Grass Knot
- Dark Pulse (Used to be U-Turn, helps explain the Naive Nature and filler attack EVs)
Azumarill @ Choice Band
Ability: Huge Power
252 HP / 252 Atk / 4 Speed
31/31/31/X/31/X
Adamant Nature
- Play Rough
- Waterfall
- Superpower
- Aqua Jet
Gengar @ Focus Sash
Ability: Levitate
252 Sp. Atk / 252 Speed / 4 HP
X/31/X/31/X/31
Timid Nature
- Sludge Bomb
- Shadow Ball
- Thunderbolt
- Destiny Bond
Garchomp @ Yache Berry
Ability: Rough Skin
252 Atk / 252 Speed / 252 Def
31/31/31/X/31/31
Jolly Nature
- Outrage
- Earthquake
- Stone Edge / Fire Fang (I alternated between the two, I didn't use either of them at all, so it's your personal preference)
- Swords Dance
For singles, I used Kangaskhan, Greninja, and Azumarill. One of the best megas for the Maison with two backups that can do a quick clean-up if it fails, or a ghost type pops up.
I would post the battle video here, but it's the first boss I beat, and I forgot to save the video. Oops. Nothing too special, so no big loss.
For doubles, I used Gengar, Kangaskhan, Greninja, and Azumarill. Just like singles, except with a Destiny Bond spammer that helps attract attention away from Kangaskhan at times, along with immediate help with ghost types, so a switch-out isn't needed.
Battle Video: 8XQG-WWWW-WWW3-D9Z4 - Nothing too special with this one either.
For triples, I used all 6, leading out with Gengar, Kangaskhan, and Talonflame. Priority Tailwind and immunity to Earthquake on both sides to start is really helpful to distribute as much damage as possible.
Battle Video: HFDG-WWWW-WWW3-ELKR - Hax out the ass on both sides with this one. I ended up winning by a Thundermiss on Azumarill from a Regice that probably would've made me lose.
For rotation, I used Kangaskhan, Talonflame, Greninja, and Azumarill. Although the AI in rotation is REALLY tricky here, it also has a good chance to try and predict things and screw up, so Pokemon that need setting-up can be exploited here, if you're feeling lucky.
Battle Video: 3T6W-WWWW-WWW3-FSQ3 - Again, nothing too special.
BONUS: NRRG-WWWW-WWW3-FSPV - My first run of rotation ended with me getting predicted and haxed the hell out of by the AI. Just an amusing side-note, I guess.
I do admit that I use a lot of really overused / unimaginary Pokes here, but it's against cheating AI that could care less while it sends out 3/4/6 legendaries that counter your entire team, so hopefully this will give those having trouble a few ideas.
EDIT: Oh yeah, my streaks are still ongoing, I'm just letting them sit at 50 while I get the last trophy for now. And apologies for the long first post.