Well, let's see...here are my suggestions for characters to host.
Basic Movement: Kamesen'nin/Master Roshi. As the first thing he teaches Goku and Kuririn are, basically, how to move properly...
Basic Combat: Grandpa Gohan. Since he taught Goku the basics of combat...
Basic Defence: Yamcha. Just a character I think should be in here somewhere and who could teach this.
Battle Management: Mutaito. He's the one who really introduces ki.
Moderate Movement: Korin, as he really put Goku through the movement ringer.
Moderate Combat: Tenshinhan. He's very good at combos and such.
Moderate Defence: Kuririn. A fairly defensive fighter.
Burst Mode Functions: Gohan, since he has a knack for these kind of sudden power bursts.
Advanced Movement: Mr. Popo, who REALLY really put Goku through the movement ringer.
Advanced Combat: Vegeta, as he's all about the rapid ki volleys and gigantic blasts.
Advanced Defence: Piccolo, as he's basically the most cunning defensive fighter in the series.
Struggles: Goku. Very good at clashes of all kinds, and he should be in here somewhere.
Extra Abilities: Mirai Trunks. He's the first one who popped into my head as someone who transforms, uses weapons and items, and taunts (eg against Freeza and King Cold).
Team Abilities: Goten and Trunks, for obvious reasons. Either as kids or teens. (I vote teen, for all the innuendo you can slip in, but that's just me

)