Cassius would make the best professional politician, I think, though I wouldn't vote for him. He is good at twisting language and twisting situations to gain the outcome he desires.
Antony seems to make the best soldier because of his loyalty and his willingness to follow through on a mission.
In his noble qualities, Brutus would make the best citizen and friend, but he does not make the best soldier. Marc Antony gives his epithet:
He only, in a general honest thought
And common good to all, made one of them.
His life was gentle, and the elements
So mix'd in him that Nature might stand up(5.5.77-81)
And say to all the world, “This was a man
And, ironically, it is Antony who would make the best politician because he has no scruples to set aside in his desire to rule. And, Cassius is the soldier because he thinks of important stategies such as allowing the Philippi to advance rather than his and Brutus's forces.
Well, I think the best friend would be Brutus, because he is such an honest individual and has such high ideals. You would always know where you were with him, because he does not try to deceive and manipulate you like others in the play does.
I think that none of them in this story would make a great citizen. this is because the politician murders another politician a friend betrays a friend and a spouse and a solider would have nothing to do with a great citizen. Atleast in this story. because in the end only 1 spouse is left and that spouse is not even loved by the husband and for the solider well i think it would be Mark Antony but i think he wasnt a great citizen