Seraphina is firmly middle name territory imo it does harken back to the Victorian era where I imagine an ethereal woman attracting great fascination from those around her, but it sounds a bit much for a first name
Sapphira - that’s a no from me
Ivy - don’t like... itchy-sounding
Iris - I love Iris Dement! And Iris is a nice enough name, but someone once told me (back when I liked the name myself) that they’ll call her “Iris the Virus,” so I’ve never considered it since. I haven’t seen that come up, though, and you can twist any name into something bad. I’ll rate this name as OK :)
Ottilie - not my cup of tea and would strongly discourage you from using this
Lilith - I’ve seen this suggested on naming boards, but the association, whether justified or not, is too strong and Lilith has yet to be reclaimed as a feminist figure in popular culture, so I would dissuade you from using this
Of your list, Iris is the best.
I’ll suggest:
Alice Seraphina
Laura Seraphina
Eve Seraphina
Isabel Seraphina
Best of luck! :)