Sorry, the Octane API exports the nodegraph that is currently rendering to ORBX, so it handles everything. The only way to get around this is with the workflow I posted above.So if you have only transformed meshes you can export them as alembic (only takes a few seconds instead of minutes or hours) and import without a problem in octane standalone. The only downside is that you have to make the material connections by hand. So i thought there might be a way for you to change (or let the user change) the way the alembic file is created. You repeatedly said this is not possible for you and i'm willing to believe you but it's hard to do so because it seems to be so easy to get this animation out of modo.
Paul