Went into this thinking it'd be a relatively short list. More fool me I guess.
1. Jump Franchises only: Might include 'Guest Characters' down the line in omakes. no promises.
2. Previous Jump Game Rosters apply: Need i say more?
3. Only series with Anime Adaptation: Any form of animation (Anime, OVA, ONA) qualifies for consideration.
4. Mostly, but not Limited to, Combat-Oriented Series: Quite a few Gag-Manga characters can go toe-to-toe with Battle-Mangas. Just as Arale-chan.
5. NO SPORTS MANGA: Don't ask.
Blue Exorcist: Surprisingly there's a good few characters who can be used for this series. And since the MC is a sword user that makes him perfect for the new 'Swordsman' Class that's supposed to be released later.
Rin: Unsurprisingly, our protagonist gets included. His Awakened State would likely be his Full Devil Form
Yukio: Possibly Rin's 'rival' on the side of the venoms. His Awakened State would be his 'Satan Flame Eyes'.
Ryuji/Bon: Staff/Spell user. His awakned State involves summoning Karura to seal opponents in a flaming barrier.
Renzo: Staff User/Martial Artist, possibly a triple agent(?), can summon high level Demons.
Izumo: Attacks with Mike & Uke, her awakened state would be her Purification for Repose form.
Mephisto/Samael: Secret character, not available during story mode. Most of his attacks involve clocks/time.
Shura: Swordswoman, most techniques involve her sword, though she has some Tamer abilities as well.
Arthur: Swordsman, wields a so-called 'holy sword'.
Amaimon: Martial artist, his awakened state is his true devil form.
Todo: The man who led to Yukio's downfall. would probably appear as an npc.
Blood Blockade Battlefront: Libra would most likely be independant of Jump Force itself, due to their resolve to ensure the tentative balance of Hellsalem's Lot, but that doesn't mean they won't offer to help kick ass.
Klaus: Martial-artist, boxin style. His awakened state is his 'Beast/Furious' mode where he does damage & gains super armor. Ult seals people in crosses.
Zapp: Swordsman, can ignite his blood to burn opponents, his Awakened state is basically his 'super focused' mode.
Steven: Kick-based Martial Artist, Ice user, awakened state deals freezing damage to nearby enemies.
K.K: Gunslinger, uses a variety of weapons icluding remote control drones to take out foes.
Hummer & Brody: BIG brawler, simple moves but hits hard.
Zed: Lancer, wind user, possesses similar movesets of Zap. (Tag-Finishers?)
Curious: Time based abilities, his Awakened form resembles his 'clock body'.
Leonardo: Part of recon department
Chain: Recon department.
Patrick: Sells upgrades/weapons/moves.
Dragonaut - The Resonance: Admittedly, I'm torn between basing characters off the Manga or Anime, since some of them are really different depending on the medium. Also, mostly Dragons in this.
Toa: Martial Artist, fights by creating barriers to block opponents, Her finishing move involves assuming her Dragon Form seal foes in a barrier.
Gio: Swordsman, his finisher involves becoming a dragon before slashing the for with his sharp horn.
Howlingstar: Lancer, his finishing move involves becoming a Dragon to drill through foes.
Machina: Water user, can attack with liquid whips & concentrated balls of water. In Dragon form she can unleash countless ice crystals from her wings.
Amadeus: Gravity user,unleashes large bursts/waves of gravity.
Garnet: Swordswoman, supposedly a Dragon. Likely allied with Venoms.
Widow: Can shoot fibre strands from her fingertips to ensnare/cut objects & put people to sleep with her nails.
Ostrum: Fire user, able to create bursts of flames & incapacitate foes with blinding lights.
Belurum: Venom allied dragon that can disrupt the connection between an artificial dragons &their partners & force them to obey.
Embalming - The Another Tale of Frankenstein: Again, as this series is apparently set during Victorian Times, expect Time-space shenanigans to explain their presence in-game.
Fury: MC, his awakened state grants him super-armor & allows him to attack at range with lightning.
Ashuhit & Elm: Gunman, electicity user. His Finisher involves a combination attack with Elm.
John Doe: Martial Artist, fights by launching high-preassure blood from his hands.
Dr. Peaberry: Works as part of the medical team.
Little Rose: John's attendant.
Edel: A Mudlark who Fury has vowed to protect.
Tiger Lily: Enemy Support character.
Lord Corpse: Frankenstein creator allied with Venoms.
Maerchen Maedchen: Could base their story-arc on the last 2 episodes which never aired before the deadline. Sadly, I don't know enough about this series to recommend who to join, so suggestions welcome.
Modern Magic Made Simple: Another series I know next to nothing about. Anyone who cares to reccomend characters from this series is more than welcome, just give good reasons for it.
Psycho-Pass: Another series i know little about, and since it's set in the future Time-Space shenanigans apply. Since Season 3 occured after the deadline, most stories revolving around this series would be set then.
Seraph of the End: More swordsmen, yey. Seriously, the Swordsman update is sure taking it's sweet time, but then to be honest I've only myself to blame for expecting new content from this game.
Guren Squad: Yeah pretty much the entire main cast should be playable.
Mikaela: Rival Character, his awakened State transforms him into a full Vampire.
Twin Star Exorcists: A series I've been meaning to get into for some time now, though admittedly it's mostly because we need more magic users in my opinion. Shame Fairy Tail isn't a Jump series...
Rokuro & Benio: As the titular characters, they fight as one. Their 'Awakened State' assumes their impurity forms.
Twelve Guardians: Would also be paired together as they are in the Anime (Mayura & Shimon for example).
Seigen: Mayura's father, acts as a trainer for 'exorcist' skils. Amawaka (天若 清弦, Amawaka Seigen)
Voiced by: Junichi Suwabe (Japanese); Doug Erholtz (English)
Yuuto: Main antagonist, allied with venoms to achieve his goals.
The Basara: allied with Venoms for survival.
Ultimo: This one is a tough one, though i reckon the fighting style would be similar to Kankuo from the Ninja Storm games, where the 'Master' stands back and allows their Karakuri Douji to fight from a distance but can still be injured at range.
Yamato & Ultimo: Puppet User, his 'Awakened Finisher' transforms him into his giant robot form.
K & Vice: Main antagonist, likewise his awakened Finisher involves his giant robot form.
Jealousy & Rune: Sin of Envy & Yamato's best friend, both desire him in some way. Independent faction/Frenemy.
Murayama & Sophia: Seeks to capture Dunstan.
Dunstan & Milieu: Neutral observers to the conflict.
Makoto & Regula: Dunstan's daughter, possess the ability to alter memories.
Good grief that took forever.
I tried a few new things, like characters who are essentially two in one here for gameplay purposes but i digress.
If you've got any suggestions for characters that would be playable, or how to best integrate characters into the story, feel free to make them known in a review!