do we know abt the birth circumstances abt any other characters outside of harrow, gideon and ianthe/corona?

Relistening to gtn and theres a snippet in the 5ths dinner at caanan house where ianthe mentions they had to pull her out after corona and how corona took her oxygen with her (which im interpretting as a shared placenta) and it got me wondering if an aspect of necromancy has to do with the idea of there being a boundary being thin between life & death & near death experiences as a bb