The restrictions are
1) Each character should have only 2 espers, except for one which will have 3
2) There should be minimum one Level 3 Esper per character, except for two which will have Level 2 Esper
3) Allocation is done on basis to unlock as many useful augments, technicks and magicks (in this order) as possible. Weapons and Armour are considered after these factors, which the exception of Makara.
Credits to Final Fantasy Fandom Wiki
Bear in mind I have already assigned roles to the characters as follows in my previous post:
Basch (highest Strength): Monk, Machinist
Ashe (highest Magick): Black Mage, Red Mage
Fran (highest Vitality): Foebreaker, Uhlan
Balthier (highest Speed): Hunter, Archer
Penelo: White Mage, Bushi
Vann: Knight, Time mage
I do have difficulty in assigning espers to the characters because of the restrictions. Mostly the licenses overlap and would not be useful to unlock using Espers. The ones which are clearly the choice is highlighted in yellow. Then the non-highlighted ones are second choices. The remaining ones highlighted in blue are loosely decided.
Here's a listing of the licenses unlocked by each Esper and also the assignment done on the character.
Belias - Level 1 Esper (Fran - Foebreaker/ Uhlan)
Knight: Potion Lore 1
Foebreaker: Horology
Bushi: Libra
Mateus - Level 1 Esper (Vann - Knight/ Time Mage)
Ulhan - Magick Lore x2
Knight - White Magick 7 & 8
Time Mage - +270 HP
Black Mage - Handbombs 3
Hunter - Gil Toss
Zalera - Level 1 Esper (Balthier - Hunter/ Archer)
Monk - Traveler
Time Mage - Ether Lore 3
Foebreaker - Traveler
Black Mage - Steal & Poach
Bushi - Bloodsword and Karkata
Hunter - +435 HP
Adrammelech - Level 1 Esper (Fran - Foebreaker/ Ulhan)
White Mage - Battle Lore & Soul Eater
Ulhan - Battle Lore
Time Mage - White Magick 4
Foebreaker - Battle Lore
Hunter - Shades of Black
Shemhazai - Level 2 Esper (Ashe - Black Mage/ Red Mage)
White Mage - +230 HP
Machinist - Handbombs 3
Red Mage - White Magick 7
Knight - Potion Lore 2
Monk - Potion Lore 3
Archer - Heavy Armour 10, 11, 12
Black Mage - Heavy Armour 7 (wasted)
Bushi - Shield Block
Hunter - Guns 5 & 6
Hashmal - Level 2 Esper (Ashe - Red Mage/ Black Mage)
Ulhan - Bonecrusher
Red Mage - Steal
Knight - White Magick 8 & 9
Monk - White Magick 4
Time Mage - Channeling
Foebreaker - Swiftness
Black Mage - Makara
Hunter - Bonecrusher
Cúchulainn - Level 2 Esper (Penelo - White Mage/ Bushi)
White Mage - Libra
Uhlan - Wither
Machinist - Magick Lore
Red Mage - Black Magick 9 & 10
Knight - Battle Lore
Foebreaker - Shades of Black
Bushi - Stamp
Hunter - White Magick 12
Zeromus - Level 2 Esper (Basch - Monk/Machinist)
White Mage - +270HP
Machinist - Makara
Red Mage - Channeling
Monk - Sight Unseeing
Time Mage - Addle and Shear
Foebreaker - Magick Lore x4
Black Mage - Heavy Armour 9
Bushi - Magick Lore x2
Exodus - Level 2 Esper (Penelo - White Mage/ Bushi)
White Mage - Battle Lore
Machinist - Green Magick 1
Red Mage - Heavy Armour 8, 9, 10
Knight - +350HP
Monk - Souleater
Time Mage - Battle Lore
Foebreaker - Magick Lore x4
Black Mage - Heavy Armour 8
Bushi - +500HP
Hunter - Stamp
Famfrit - Level 3 Esper (Ashe - Red Mage/ Black Mage)
White Mage - Daggers 5 & Numerology
Ulhan - Potion Lore 3
Machinist - Time Magick 8, 9, 10
Red Mage - Battle Lore x2
Monk - White Magick 10
Time Mage - Battle Lore
Foebreaker - Magick Lore
Archer - +390HP & +435HP
Black Mage - +190 HP, +230 HP, and +310 HP
Chaos - Level 3 Esper (Vann - Knight/ Time Mage)
White Mage - +310HP & Greatswords 2
Ulhan - Black Magick 7 & 8
Machinist - +350HP
Red Mage - Greatswords 3
Knight - +390 HP, Revive, and Excalipur
Monk - White Magick 11 & 12
Time Mage - +270HP
Archer - Magick Lore x5
Bushi - Brawler
Ultima - Level 3 Esper (Balthier - Hunter/ Archer)
Ulhan - Expose
Machinist - Magick Lore x3
Red Mage - Greatswords 1 & 2
Knight - Telekinesis & Battle Lore
Monk - Swiftness x2
Time Mage - Swords 7 & 8
Foebreaker - Swiftness
Archer - Infuse & 1000 Needles
Black Mage - Telekinesis
Bushi - Stamp
Hunter - Phoenix Lore x2 (wasted)
Zodiack - Level 3 Esper (Basch - Monk/Machinist)
White Mage - Greatswords 1
Machinist - +390HP
Red Mage - Greatswords 4
Knight - Excalipur, Revive, and +390 HP
Monk - White Magick 13
Time Mage - Swords 9
Archer - Infuse & 1000 Needles
Bushi - Heavy Armour 9, 10, 11
