Who can absorb the Genki Dama?
So far there has been no reference to another person who can absorb the Genki Dama other than the creator, which happens accidentally in the latest Dragon Ball Super episode. Hypothetically speaking, I don't think a person with good ki can absorb it, although they aren't harmed, A Genki Dama Bomb is still an attack used to defeat foes who's ki isn't 'good', So it is safe to assume that Goku will only use it against people he knows it'll harm. Having someone with good ki absorb it would most probably make them OP so it is probable that it is introduced later in order to defeat a strong character.