things about the duplex au
not a “canon” exactly but more like details
the cats’ appearances are affected by the way(s) they died but it doesn’t have to be major or literal.
for example, Bristlefrost might always have black dew shining in her fur from drowning. Hawkfrost was killed twice by Brambleclaw/star so he has vines and thorns sticking out of his fur.
each double-dead cat has an ability that they can discover once they’re in the duplex, but they discover their abilities rather than automatically knowing what they are
a lot of them are dark forest cats just because the majority of the dark forest cats had spirit deaths (between the last hope and alitm they’re almost all gone)
cats that “fade” rather than dying spirit deaths are also around but maybe they can come and go rather than being confined