Based on my experience and the general core of my team through my playthrough
Alolan-Muk (Britney): A+
+Can conceivably use in any gym as it can live any one hit and deal back massive damage
thanks to its great movepool in (at least what I use) Knock Off, Gunk Shot, Poison Jab, Acid Armor
+Even with mine being Modest, still is more than capable of being an offensive threat
+Poison touch comes in handy all the time, scoring 60% poisons with poison jab
+Been Ol' Reliable MVP of the team
-Doesn't evolve till 38
-Only one through the shadow capture, so at mercy of waiting to find out if you have terrible Power of Alchemy is iffy
-Slow
Vikavolt (Moses): B+
Seems high, hear me out.
+Again, never had an issue in any gym other than Amber's with a Modest Thunderbolt, Bug Buzz, Agility, Charge Beam/Energy Ball set, easy 6-0 on Valarie
+Typing is just incredibly useful through V9
+145 SpA might be highest available (w/ Chandelure) at this point (someone check me out on that)
+77/90/75 defenses allow you to get some key survivals to blow someone back
+As a Charjabug, allowed me to sweep Keta with 110 base power acrobatics, no joke.
+/- call it as you will, you can't get until Terajuma and potentially pass up Bug Buzz by level up. Mine was 35 when it evolved so I wasn't too disappointed to
reverse candy up to 31 and get Bug Buzz. Very much worth it.
-Slow, common theme with my team
-A majority of the level up moves are physical, while they have great coverage, it doesn't utilize Vikavolt to its strengths.
Chandelure (Bray Wyatt): B+
+Great failsafe option with magma drift, will-o-wisp, minimize and shadow ball; brings back potential loses into wins with key evasive qualities
+145 SpA once again
+From the time its available, its typing is useful in all gyms
-Slow as hell to level up. I had no issues cause my team was about 60 at the time and i slapped an exp. share on it
and quickly got it up to speed on Audinos
-Need a Dusk Stone and they are scarce, I believe only two are available at this point
-Pain in the ass to get really, the Litwick side quest does require a lot of work and powerful mons to get to this point.
Diggersby (Roger): A
+Return with a silk scarf ends lives with Earthquake
+Actually can surf and serves as a solid HM slave since you really only need EQ, Return, Agility/SD and filler
+Available fairly early
+Pure Power, that is all
-Might get pickup or cheek pouch, just catch another, no biggie.
-Not the fastest Rabbit around
-Kinda niche, I temporarily dropped him at Valarie and wasn't useful for Flora either except as heal fodder
Tangrowth (Vermicelli): B+
+Regen is very nice, although I had chlorophyll (useless)
+Sleep Powder, Stun spore are great options
+Sludge bomb, giga drain, stun/sleep and knock off are great support set options with 100/110 offenses
+Bulky Bulky Bulky physically with 100/125.
-Slow as can be
-SpD is a Joke and no AV yet to patch that stat up such as it is used in OU
-Eaten alive by Amber and Crawli's team, so it lost usage and I replaced him with a Minior at these times
Greninja (My Black Son): A+
Yeah, yeah, yeah I copped out my choosing Froakie and soft reseting till I had a Timid, Protean one, but I'm not here to win respect.
+Fast, Fast, Fast
+Can use in any gym really because of Protean and good coverage
+Shuriken is great priority to break sturdies and hit decently in doing so
+Great Revenge Killer
-No Dark Special Stab available, best move is Night Slash and you need a Heart Scale
-Kinda weak without a Sea Incense/Mystic Water
-In earlier evolutions, doesn't have really any strong attacks and you're basically stuck with Water Pulse and Smack Down for a while
Lemme know how I did frens
I also used Xatu, Minior, Mega Heracross, Bellossom, Medicham, Camerupt and Salandit (unforts, male)