Currently I am trying to figure out how to shatter a shell mesh on top of (on the outside of) an internal mesh.

I have generated a shell around a human figure using a copy SOP with metaballs, converted the metaball shape to a mesh using “remesh”, and my goal now is to have the shell crumble apart on top of the underlying human mesh.

I am running into problems where intersections between the sub mesh and the exterior cause the shell to jump at the beginning of the sim animation.

Any ideas? My thought was to make initial point velocities aimed from the centroid to each vertex

It sounds like overlapping pieces. Try giving the Cut Plane Offset (Voronoi Fracture) a small value. Convex pieces have this in DOPs, but not Concave ones.