The little dolls surrounding Flandre are symbolic representations of the "ten little indians" from the rhyme.
"One choked his little self..." that must be the one directly left of the sword, who has spikes and blood coming out of his throat. "One overslept himself..." Obviously the one in the nightcap, left of the one who choked. "One said he'd stay there (in Devon)..." Not sure about this one, but by elimination it seems the one directly right of the sword. "One chopped himself in halves..." Obvious, has an axe in his head. "A bumblebee stung one..." Obvious again, right behind the nightcap one. "One got in Chancery..." The one in striped prisoner clothes, left of Flandre. "A red herring swallowed one..." The one inside the fish, of course. "A big bear hugged one..." Behind the axed guy, has a furry paw on his head. "One got frizzled up..." Completely blackened doll behind the bear one. And of course, Flandre herself is the final one. "She went and hanged herself and then there were none."