Yes, they're very much different topological meshes: one is a dynamically tessellating surface comprised of quads, triangles, and many, many poles; the other is a quaded surface with poles placed at edgeloops junctions to control edgeflow direction.
Dynamesh will not work with masks. You really don't have to bother with geo when you have a decent level of ground work done, choose half res in Zremesher (or experiment with values) and use subdivisions then. As said you can move the low subdivisions around and the go back to the higher ones. Subdivision will give a way…