If I were to backup the two RAID 2GB partitions on the MYCLOUD would I be right in thinking this would bakup all my added features such as transmission, mysql, sickbeard etc…

I ask as to unbrick the device when things go wrong you DD the ROOTS.IMG file pulled from the firmware to restore as a new device. Or am I completely wrong here?

That is correct. Infact you just need to backup one of the raid partitions. In case of debricking, you simply restore the backup image to both partitions and that brings it back to life