Forgive me for not reading all 65 posts, I did glance through most of the images though,, and seeing what you just wrote, here are my initial thoughts...
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I think your large figure is fine, but because he has the largest size, he somehow has the ironically smallest eyes. That leads him to being inconspicuous to the others who have large expression filled eyes.
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The candles are much too close to the boy, and his lighting comes up happy, not creepy. If you place it farther from the chair, to in front of the paintings, of which you could move the boarded window to where the full painting is, and move the painting to where the window is... then put the candles in front of it, and cast shadows up and high over the frames and the chair, then the light of everyone goes left... leaving deeper shadows to make one side of everyone's face be dark and foreboding.
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The vampire's cape is a deep black hole in your composition, my eye just sinks into it. i would change it to deep satiny blues or purples, also watch the pen and bottom of the boy's feet doing the same thing.
It's a great piece, don't give up on it.