The monopoles and cosmic strings kinda ruin this. But there totally might be life in the star cores made of plasma magnetohydrodynamic interactions, in fact I'd be surprised if it weren't common. And the lifeforms would be completely isolated from outside universe, by the turbulent nature of outer star layers, by the enormous gravity well and the comparatively absolute cold and vacuum of empty universe. None of the linked sci-fi stories have such life as subject (at best The Truth but that one has a creature that can exist on Earth long enough to be perceived instead of violently dissolving into loose cooling gas in microseconds), probably because it's very hard to make it interact with human characters, but it's the simplest form I can think of.