0 Beatrice

Mugshots/0_beatrice.png|0_beatrice.png

This is our codename for the Beatrice who was kept in Kuwadorian and died in Rosa's flashback.
Assuming she lived on the island ever since the mansion was completed, she was stuck in there from 3 to 5 years old until she died at around 20

She used to wear the dress we see in the portrait, so even though she died long before the painting was installed, her photos might have been used as the model.

X Beatrice is the daughter of 0 Beatrice

X was born shortly before 0's death, making her about 19 years old.

Leads:

It works timing wise.
Relatives in anime tend to look really close to each other.
The whole homunculus reincarnation story looks like a very Kinzo way of interpreting a line of hereditary succession.