new character are quite strange but i have some possible thoeries.
The boy may related to battler. Red hair is red hair after all. the anchor pendant may make him the opposittle to battler (anchor=boat=I'm going to fall)
or maybe is a representation of the younger boat captain.
The girls seems more interesting to me. somebody had the theory of she being the illegetimate child or the one kyrie saws in ep2. That's something interesting.
On the She is holding a red rose so she might be related to Maria rose.
Also in the portrait there are a golden buttlerfly on the table. Maybe the golden brooch Beatrice gave shannon on ep2.
I think that this girl is also the doll of the screenshoots. that effect on the the image before can be one like a broken doll.
I wonder what would mean the white roses
And this is all I can think without reading ep6