Can the Soul gem affect the other gems? Does it give to its user mastery over all other being with souls?
Adam Warlock has used the Soul Gem to steal the souls of living beings, to take a soul from the "Soul World" inside the gem, and inflict it upon a being that had traded away his soul, and as a more direct offensive weapon through his "karmic blast" that would KO most "cannon fodder" level opponents.
As far as affecting the other gems, probably? I think there's a chart out there somewhere that shows how each gem can affect the others. As far as old-school Infinity Watch era continuity, it was the Reality Gem that allowed some of the other gems to tap their full potential.
I would think the Soul Gem could influence the others, since it's the only one (I'm aware of) that has sentience...