Tradescantia zebrina will over-run the other plants. I wouldn't disturb the others to remove that, just snap it off. Let the severed end dry overnight, then it's ready for a pot of its' own. You can bury the cut end, or just lay it on the surface. It will take root either way.
The color depends on light exposure. That deep maroon color is its' tons-of-sun appearance. Commonly used in hanging baskets because of its' dangling habit.
(Sedum isn't a plant family, that genus is a member of the Crassulaceae family.)
