If you're struggling to find your favourite Star Wars character in the game then this list is for you.

Luke Skywalker:
Coruscant (Jedi Temple)
Mygeeto (War-Torn City)
Jabba's Palace
Death Star (Interior)
Hoth (Echo Base)

Anakin Skywalker:
Mustafar (Refinery)

Han Solo:
Utapau (Sinkhole)
Polis Massa (Medical Facility)
Endor

Chewbacca:
Kashyyyk (Beachhead)
Felucia (Fungi Forest)
Yavin 4(Temple)

Princess Leia:
Tantive IV (Interior)
Naboo (Theed)

Yoda:
Kashyyyk (Beachhead)
Tantive IV (Interior)
Polis Massa (Medical Facility)
Dagobah

Mace Windu:
Geonosis (Dust Plains)
Coruscant (Jedi Temple)
Yavin 4 (Temple)
Death Star (Interior)

Obi-Wan:
Utapau (Sinkhole)
Mustafar (Refinery)
Naboo (Theed)

Aayla Secura:
Felucia (Fungi Forest)
Jabba's Palace

Boba Fett:
Kashyyyk (Beachhead)
Utapau (Sinkhole)
Mygeeto (War-Torn City)
Felucia (Fungi Forest)
Yavin 4 (Temple)
Jabba's Palace

Jango Fett:
Kashyyyk (Beachhead)
Felucia (Fungi Forest)
Yavin 4 (Temple)

Darth Vader:
Tantive IV (Interior)
Coruscant (Jedi Temple)
Dagobah
Naboo (Theed)
Hoth (Echo Base)
Endor

Emperor:
Polis Massa (Medical Facility)
Naboo (Theed)
Death Star (Interior)

Darth Maul:
Coruscant (Jedi Temple)
Mustafar (Refinery)
Jabba's Palace

General Grievous:
Tantive IV (Interior)
Utapau (Sinkhole)
Polis Massa (Medical Facility)
Dagobah, Mygeeto (War-Torn City)

Count Dooku:
Geonosis (Dust Plains)

Ki-Adi-Mundi:
Mygeeto (War-Torn City)

To advance through the ranks you have to collect the indicated number of medals to unlock the corresponding rank.

Unlock Veteran Rank:
Get 6 medals.

Unlock Elite Rank:
Get 30 medals.

Unlock Legendary Rank:
Get 60 medals.

When you complete the indicated task the corresponding medal and bonus that come with it (brackets) will become unlocked.

Unlock Endurance Medal (Energy Recuperation):
Get 8 points.

Unlock Guardian Medal (Shielding):
Get 16 points.

Unlock War Hero Medal (Damage Increase):
Get 24 points.

Unlock Gunslinger Medal (Precision Pistol):
Get 6 kills with a pistol in one life.

Unlock Regulator Medal (Flechette Shotgun):
Get eight kills with a shotgun in one life.

Unlock Technician Medal (Vehicle Regen):
Slice into a vehicle.

Unlock Demolition Medal (Guidable Rockets):
Get four critical hits vs. Vehicles in one life.

Unlock Marksman Medal (Particle Beam Rifle):
Get 6 headshots with the sniper rifle in one life.

Unlock Frenzy Medal (Elite Assault Rifle):
Get 12 kills with a blaster rifle in one life.

When you have collected the indicated amount of medals the corresponding rank will become unlocked.

Unlock Private Rank:
Control 1 unit and have less than 20 total medals.

Unlock Sergeant Rank:
Control 2 units and have between 20 and 99 total medals.

Unlock Captain Rank:
Control 3 units and have between 100 and 299 total medals.

Unlock General Rank:
Control 4 units and have at least 300 total medals.

When you reach Legendary rank in the indicated class the corresponding bonus weapon will become unlocked.

Unlock Particle Beam Rifle:
Reach Legendary rank in Marksman.

Unlock Elite Assault Rifle:
Reach Legendary rank in Frenzy.

Unlock Precision Blaster:
Reach Legendary rank in Gunslinger.

Unlock Flechette Shotgun:
Reach Legendary rank in Regulator.

Unlock Guidable Rockets:
Reach Legendary rank in Demolition.

Unlock Vehicle Regen:
Reach Legendary rank in Technician.

During game play pause the game and press and hold L2 and R2 and enter the following codes for the corresponding effect.

Unlock Alternate Sounds:
Up, Up, Up, Left, Up, Down, Up, Up, Left, Down, Down, Down, Left, Up, Down, Down, Left, Right

Unlock Alternate Soldiers:
Down, Down, Down, Up, Up, Left, Down, Down, Down, Down, Down, Left, Up, Up, Up, Left Right

No HUD:
Up, Up, Up, Up, Left, Up, Up, Down, Left, Down, Up, Up, Left, Right

Pause game-play While playing in offline mode and input the following codes

Infinite Ammo:
Up, Down, Left, Down, Down, Left, Down, Down, Left, Down, Down, Down, Left, Right.

Invincibility:
Up, Up, Up, Left, Down, Down, Down, Left, Up, Up, Up, Left, Right.