Squid are definitely attracted to lights, which is why some of the jetties with lights on them are/were (in the case of the Woody Point jetty) great places to chase them in the winter. Commercial squid boats fishing the southern ocean use massive banks of floodlights to bring the squid to the boats. This is also why some of the squid jigs are luminous - shine a bright light on them for a few seconds and they will glow for quite a while, attracting the squid. You can also attract the squid in winter in places like the Redcliffe reefs by shining a bright light (like a pressure lantern) into the water on the calm winter nights after dusk and catching them on jigs very close to the boat when they come to the light.
Can't comment on the prawns since I've never tried prawning at night, although the plive prawns which I keep in the aquarium at home in between trips always bury themselves in the gravel on the bottom of the aquarium during the night.
Cheers Freeeedom