Rimmer discovered a way to get someone back temporarily by swapping data files in the saved game folder. The post is quoted as a reference in the imp council member quest post (link above), and described in the catacombs portal fix and
Josephine herself stuck in the wall. Since you have to restore your original data file, any experience from completed quests etc. will be lost.
You should be able to substitute a different kind of wine for Corinna.
