You’re right about update-rc.d not being available. Apparently it was removed in more recent firmware versions.
I copied that suggestion from this post but didn’t test it because I’m not interested in killing the cloud service.
However, later in the thread is another suggestion that should work just as well. Simply remove execute permission from those services. Like this:
chmod -x /etc/init.d/wdmcserverd
chmod -x /etc/init.d/wdphotodbmergerd
That should prevent those services from being able to start. I don’t plan to test it, but if you do please report what you find.
