This is right up my alley! With 4 characters to highlight, I'll post 4 different songs of varying genre / languages.
First, one of the two main protagonists: Omari Osei. His underhanded, card playing, street-smart, gambler personality is best suited with Kool G's Let the Games Begin
Next is the other main protagonist: Long Xiaolian. Their patient and pridefully passionate discipline inherited by millenia of traditions is best exemplified with DATAKEN's Spinning Song covered by Panda
Third on the list is Eileen Edwards. A journalist who's high energy, electric passion, unapologetic flirting and lust for the experience of near death has a few songs associated, but Let Mom Sleep by Hideki Naganuma from the Jet Set Radio OST is the one I'll go with for her today.
Finally, we have Raymond Reyes. For a man with unknown potential bound by a myriad of unseen chains like a savage beast, despite his quieter and almost tearful disposition, I chose Eterna Soledad by Los Enanitos Verdes
Meet all 4 of these characters here!