Let me provide a team for each starter.
Infernape team: [Infernape, Floatzel, Staraptor, Luxray, Hippowdon / Garchomp, Roserade]
Empoleon team: [Empoleon, Staraptor, Rapidash, Raichu, Hippowdon / Garchomp, Weavile]
Torterra team: [Torterra, Floatzel, Staraptor, Rapidash, Raichu, Weavile]
[The options for ground types depending upon the availability of Earthquake TM, i.e. if you can gain momentum and jump off the particular ledge in Wayward Cave]
- Flare Blitz / Fire Blast / Flamethrower
- Close Combat / Focus Blast
- Grass Knot
- Shadow Claw
Infernape is a starter. Pick Chimchar from Rowan's suitcase if you want Infernape. It can learn Close Combat and Flare Blitz by Level up (41 and 57 Respectively). Fire Blast and Flamethrower are TMs which can be used until he learns Flare Blitz. Use focus Blast if you want a Special Alternative, but it has low accuracy. Grass knot and Shadow Claw are coverages and are TMs.
Ability: Run Away / Flash Fire
- Flare Blitz / Fire Blast / Flamethrower
- Sunny Day
- Solar Beam
I wouldn't recommend you to use this 'mon. Since there are only two Fire types in DP, you might need him. Flare Blitz and Bounce are learnt by level up (level 58 and 49 respectively). Fire Blast and Flamethrower are TMs which can be used until he learns Flare Blitz. Sunny Day is just a filler and Solar Beam is for coverages (and are TMs).
- Drill Peck
- Flash Cannon
Surf and Waterfall are useful HMs. Drill Peck for Coverage and is learnt at level 52. Flash Cannon is TM.
Ability: Swift Swim
- Ice Beam / Ice Punch
Surf and Waterfall are HMs. Ice Beam is TM and Ice Punch is from Move Tutor, choose whichever is easy to obtain, it is for coverage. Crunch is neutral Coverage and is learnt at level 26.
- Wood Hammer
- Leech Seed
Wood Hammer is STAB and requires Heart Scale to obtain it. Crunch is neutral coverage and is learnt at level 45. Earthquake is Stab and is learnt at level 32 and Leech Seed for Bulky 'mons and is learnt at level 33.
Ability: Nature Cure
- Petal Dance / Grass Knot
- Shadow Ball
- Sludge Bomb
- Leech Seed / Giga Drain
Petal Dance, Sludge Bomb and grass knot are Stab. Petal Dance learnt at lvl 40 as Roselia. Shadow Ball is for Coverage. Leech Seed is for Bulky 'mons and Giga Drain heals you often.
Staraptor @ Shell Bell
- Brave Bird
- Close Combat
- Roost / Defog
Brave Bird and Close Combat are mandatory for this beast, learnt at level 49 and 34 respectively. Fly and Defog are HMs, and Roost is to heal you often. Shell Bell is located in Hearthome City.
Ability: Intimidate / Rivalry
- Spark / Thunder Fang
- Thunderbolt / Scary Face
Charge is to raise SpD and double the damage of Electric moves, learnt at level 9. Crunch is neutral coverage, learnt at level 35. Spark and Thunder Fang are good physical electric moves, learnt at level 18 and 42 respectively. Thunderbolt if you want high power electric move and Scary Face to help its poor Speed.
- Grass Knot
- Whatever TM
Thunderbolt is Stab and learnt at level 26. Strength is a HM. Grass Knot is Ground coverage. The last slot is of your choice.
Ability: Sand Stream
- Fire Fang / Rock Slide / Rock Tomb / Stone Edge
Crunch, again, is neutral coverage move. Earthquake is STAB and is learnt at level 40. Yawn puts the foe to sleep, learnt at level 13. Fire Fang requires Heart Scale, and the rest are TMs, which are coverage.
Ability: Sand Veil
- Rock Climb
- Dragon Claw -> Dragon Rush
- Ice Shard / Ice Punch
- Night Slash / Thief
- Slash / X-Scissor
- Brick Break
Ice Shard is Priority (doesn't matter since he is already fast), learnt at level 49 as Sneasel. Ice Punch is difficult to obtain (move tutor). Night Slash is Stab, learnt at level 35 as Weavile. Thief is 60 base power TM which you can use. Slash is high crit hit, is neutral coverage, learnt at level 35. X Scissor is just neutral coverage and is a TM. Brick Break is for coverage and is a TM.
Roark (Rock): Handled by the starters.
Gardenia (Grass): Handled by Monferno and Staravia
Maylene (Fighting): Handled by Monferno and Staravia
Crasher Wake (Water): Handled by Luxray, Roselia and Raichu
Fantina (Ghost): Handled by Floatzel and Luxray
Byron (Steel): Handled by Infernape, Staraptor, Torterra, Gabite, Hippowdon and Rapidash
Candice (Ice): Handled by Infernape, Staraptor and Rapidash
Volkner (Electric): Handled by Torterra, Gabite and Hippowdon
Aaron (Bug): Handled by Staraptor, Infernape, Rapidash and Weavile
Bertha (Ground): Grass Knot Sweep
Flint (Fire): Handled by Hippowdon, Floatzel, Rapidash or Infernape and Empoleon, Garchomp
Lucian (Psychic): Handled by Infernape, Rapidash, Floatzel, Luxray, Torterra, Hippowdon, Garchomp and Weavile.
Gastrodon: Grass Knot
Roserade: Rapidash / Infernape / Staraptor / Weavile
Milotic: Grass Knot / Thunderbolt
Lucario: Infernape / Staraptor / Garchomp
Garchomp: Weavile / Floatzel
You see, how many times Infernape has repeated, clearly stating that it is a suitable starter.
The ground Types I have mentioned can learn Earthquake by level up, where it is difficult to obtain a TM.
These items make the sweeping gyms and E4 easy (Optional)
Dread Plate (Dark) - Fantina and Lucian
Location: Old Chateau
Earth Plate (Ground) - Byron, Volkner and Flint
Location: Oreburg Gate
Fist Plate (Fighting) - Byron and Candice
Location: Route 215
Icicle Plate (Ice) - Cynthia
Location: Route 217
Miracle Seed (Grass) - Crasher Wake, Bertha
Location: Floaroma Meadows
Mystic Water / Splash Plate (Water) - Flint
Location: Pastoria City / Route 219
Hope this helps :)