DID SOMEONE SAY DRAGONBALL CHARACTER PERSONALITIES???
BECAUSE I THOUGHT I HEARD SOMEONE SAY DRAGONBALL CHARACTER PERSONALITIES!!!
GOKU:
-Is a Child
He remains a child throughout his entire life and DOES NOT CHANGE AS HE AGES. That is VERY IMPORTANT to the character of Goku. He learns more things but he never acts differently.
-Is Extremely Stupid
He's a retard. His extreme naivete is really his most important feature and while this doesn't often translate to bad tactical decisions, when he makes good tactical decisions there's a good chance he's just operating on instinct and doesn't really understand the reasoning behind anything he does. One of his best defining moments is when he shows Gohan to his friends for the first time and they are all STUNNED that he (Goku) knows what sex is. In fact, it's not unreasonable to imagine that even after having HAD sex Goku has no idea what sex is. He thought marriage was a food.
-Loves to Fight
What I imagine would be most important to you translating this game is that when Goku is up against a terrible opponent (unless that opponent just killed one of his friends) Goku is always thinking "wow it'll be fun to fight this guy" before "wow I better defeat the shit out of this guy before he does something really fucked up to the universe". The first time he squares off against Cell and Buu he makes it clear that he considers it a great honor to be able to fight people as dangerous as them. This translates into his teaching style in basically the way you'd expect, he's very gung-ho, plus his unending optimism means he's a great positive motivator. When training Gohan he has to rely on Piccolo for the "tough love" stuff though.
-Loves to Eat
Standard anime hero trope. He can and has eaten enough to feed a large army in one sitting.
-Loves All Life
He only intentionally takes one life in the entire run of the manga, Piccolo Daimaou. He means to kill Frieza, albeit way after ANY other character would have long since gotten tired of Frieza's bullshit and ended his sorry ass, but Frieza survives his final attack. Buu doesn't really count because Goku only kills him when he's utter pure evil and wishes him back in the form of Uub almost immediately. Lives have indeed been lost because of Goku's reluctance to kill and continued insistence that everyone can change, on the other hand, lives that do become worthwhile and instrumental to the survival of the universe have been SPARED this way, such as Piccolo and Vegeta.
GOHAN
-Is Extremely Smart
Throughout his young life he's been constantly pushed by his mother to study, study, study, something which has been undermined by Goku, who just wants to teach Gohan how to fight, whenever they both can get away with it. Gohan really does like books more than fighting though, and by the time of the Buu Saga he's trying to put fighting behind him.
-Is Extremely Strong, Especially When Angry
Gohan has absurd potential as a fighter, and experiences LUDICROUS power spikes when he's pissed off, usually at the death or perceived death of someone he loves. This is eventually weaponized in the form of SSJ2, which Gohan is the first in the universe to attain.
-Is Pretty Timid as a Child
He mostly gets this from his mother, and it isn't until he hits SSJ2 that he truly puts fear behind him. From an extremely young age, however, his berserker rage mode completely disregards fear.
PICCOLO
-Is a Villain
This is something that's really played down in the American dub of DBZ since we didn't get Dragonball first and no one knew he used to be a villain. There he's basically this wise but cranky guy that doesn't like Goku very much. In truth, though, he's the cold blooded reincarnation of a Namekian, Piccolo Daimaou, who is the PURE EVIL HALF of the Namekian Kami, discarded so that Kami could become, well, the Kami of Earth. He is not pure evil as Daimaou was, but he still has the heart of a killer and until he settles down around the Namek Saga would GLADLY kill Goku. And while he has settled down by that point, he gets a great speech during the Android Saga where he makes it very, very clear to Dr. Gero that he is NOT LIKE THE OTHER Z-FIGHTERS, who would probably spare Gero's life if Gero pleaded. Piccolo is a killer and will not hesitate to do so if he feels the situation calls for it.
-Loves Gohan
Piccolo kidnaps Gohan to train him to defeat the Saiyans early in the show. He does this simply for pragmatic reasons since he thinks, rightly, that it will give the world more of a fighting chance if there are more strong fighters for Earth, and he doesn't want the Earth to be destroyed, he just wants to rule it. As time goes on though, he finds himself bonding with Gohan and by the time the Saiyans arrive, Piccolo ends up sacrificing himself to save Gohan. Now, that doesn't mean he's not still very gruff and cranky with Gohan, but it does mean he won't ignore him or try to kill him.
-Is Extremely Intelligent
Piccolo is a master strategist and is by far the most logical of all the Z-Fighters.
VEGETA
Vegeta's probably the most dynamic character in the entire story. He goes through the most changes and really is the most different at the end.
-Is Royalty
Vegeta is the proud warrior prince of a dead race, which doesn't diminish his sense of entitlement at all. He's pompous, murderous, and he gets to be this because he's the strongest there is. He loses to Goku in the Saiyan Saga only because of the interference of Goku's friends; he is CLEARLY a much stronger fighter than Goku at that point. Overall he is an utter genius at combat, impressing even Piccolo with his capacity for tactics and bluffing.
-Is Obsessed With Being the Best
After Vegeta sees on Namek that Goku has completely outclassed him, he becomes completely obsessed with taking the lead again. He trains like a man posessed to attain SSJ after Goku does it and every time Goku effortlessly surpasses him it infuriates him even more.
-Loves His Family
As he is constantly trying to surpass Goku his time on Earth is changing him, though he doesn't realize it at first and then won't admit it to himself. He truly loves Bulma, his wife, and his son Trunks, but finds himself so completely overwhelmed by how completely this flies in the face of his Saiyan upbringing that during the Buu Saga he allows himself to be powered up by Babidi to match Goku's SSJ2. Babidi thinks that Vegeta is under his control but Vegeta's will is far too strong; he is truly just giving into the animal within. After his actions result in Buu being released, Vegeta realizes what a fool he's been and tells Trunks that he loves him before sacrificing himself in a final explosion he hopes will destroy Buu. After this fails and he's brought back to continue to help the fight against Buu, he swallows his pride and sets his rivalry with Goku aside. He still doesn't like Goku, but he respects him and he's willing to settle for being second best.
If you need any more just let me know!