As others have said, capacitors may be at risk if frozen. If any components have printed circuit boards, there is also some danger from solder spiders if the humidity and electrostatic charge is just right. Not an issue with point to point wiring.
Recommend that everything be disconnected; remove all power cords and interconnects. Wrapping/sealing is a good idea. When returning, after unwrapping/unsealing allow to acclimate at least 24 hours before reconnecting and repowering. You may also want to deox all the connection and power contacts.