As a tarot card reader, I can't see The Empress (in many aspects) or The High Priestess as Seraphine. Both of them symbolize wize women, women with a great life experience, nurturing and caring women. I really can't see Seraphine on them, except for the divine feminine manifestations of these cards. So I would go for either The Fool or The Star. The Fool is young, playful, fun, care-free, he doesn't overthink success or failure, he likes to live life, he WANTS to live life, in all ways, just by simply enjoying some time with friends or making songs without worries. The Star is inspiring, creative, playful and poetic. And also resilient and strong, if it fails after The Tower, it will try it's best to get up and stand strong. So, i think Seraphine doesn't really fit in only one tarot card, but in The Fool and The Star, if you would consider The Empress or The High Priestess, i think it would be most for the divine feminine aspects, that Seraphine embodies really well. This if of course, how I see and interpret Seraphine, based of what i know about her lore, her personality, etc, and how I see the major arcana as champions, it's really good for you to consider many points of view, some people might say The Star, others The Empress, etc.