First MOC

TL;DR:

• lego - on everything
• lego-cinematic-universe - on LCU works, always use with lego and work
• lego-work - about the work - always use with lego and lego-cinematic-universe (if appropriate)

I propose

• using lego as the "general" tag; it will be use on all LEGO questions. The rationale is that someone looking for lego stuff might be remotely interested in other LEGO-related tags. ID questions would then be tagged lego+character-identification or lego+object-identification, and tag description would be edited in consequence. 16 questions to retag
• using lego-cinematic-universe for this universe (duh), the way dc-extended-universe or marvel-cinematic-universe work. The idea is to encompass current movies/games/shorts in this universe while excluding lego-star-wars-like tags (which, as far as I know, aren't part of the LCU); 6 questions to retag
• using lego+relevant-lego-tag for other works. 8 questions to retag

Cross-universe cases:

• tag the-lego-batman-movie with dc too, as there's a DC stamp to it;
• tag lego-star-wars with both lego and star-wars for the same reason.

Seems fairly in line with what's done with other materials/franchises, and (though my figures might be slightly off) the amount of retagging involved can probably be done smoothly over a week or so.