It looks likely that you were correct in marking this as specific to Nouveau. After switching to the proprietary Nvidia driver I have had 48 hours of uptime with no issues. Thus, I no longer have a personal stake in seeing this bug fixed. However, if there is any further specific data I could collect to assist in debugging, I'll go back to Nouveau temporarily.
It looks likely that you were correct in marking this as specific to Nouveau. After switching to the proprietary Nvidia driver I have had 48 hours of uptime with no issues. Thus, I no longer have a personal stake in seeing this bug fixed. However, if there is any further specific data I could collect to assist in debugging, I'll go back to Nouveau temporarily.