We do have unique ID's for each production (and have already had to deal with avoiding duplication of shows with the same name) but linking to Wikidata is a good shout!

I've not looked into it fully but since we cover a lot of Fringe and Amateur productions they might not be in Wikidata and those will tend to have a higher duplication factor.

mix n match is a tool for reconciling such lists:

https://mix-n-match.toolforge.org/

Looks like they already have a few databases with opera singer and writers as well as actors etc.