Following up on this, meanwhile I’ve done a very brief test using curves hair & geo nodes. It’s actually pretty straight forward: in order to animate the curves hair you need a proxy mesh, a vertex-by-vertex copy of the curves hair that will be manipulated, vertex positions will be copied back to the curves hair via geo nodes in a very simple procedure: transfer attribute by index which works as long as proxy and curves maintain the exact same count and order of vertices.
The deformer geo nodes are “hair_deform” in the Einar sample file. Use them as first geometry nodes modifier in the groom object’s modifier stack. Add whatever node setups you like atop to refine the groom.
In order to create the proxy you can use another node group from the Einar grooming file, “generate_proxy”.
For more details also see this thread: Rig and simulate Hair Curves on Blender 3.3
As I do my grooms inside Houdini and export them together with procedurally created rigs I take the other way round though: I convert a copy of imported hair strands (mesh) into curve, then curves, and add the “hair_deform” group using the original, rigged mesh as target → works!
I reckon that means it will be possible to import animated grooms from other DCC applications as well. Will test that soon too …