As far as I can think, all we really know about Jonas is that he has pale eyes where everyone else in the society (just about) has dark eyes. We also know that, unlike Fiona, he does not have red hair.
As far as other traits, his most important trait is his caring about feelings. He wants other people in the community to be able to have the rich feelings that he has now experienced because of the memories the Giver has given him.
As for actions, of course the important thing is that he goes from acting just as society demands to doing things that will destroy his society.
he eat dookie