just a heads up that dead dove: do not eat doesn’t actually mean anything by itself, it's not a category of fics. It just means: what you see/tag is what you get, so read the tags again.
The tag is mostly used for dark themes and fics because it acts as an extra warning "read the tags again that's what you'll get" but you could use it together with "eating cake" to mean "yes they will actually eat cake in this fic"
Anything and everything can be used together with DDDNE but it is up to the writer to decide whether or not to use it and when they feel like using it