So, feedback again? I'm sorry if you feel it's too random, but I like talking. XD
The first one is my fav, again. :D I really like the transparency, the sepia-like color, and the blurry image in the foreground (even though I can't really see what it is, it gives a soft vibe to your whole poster so it's perfect). The pictures, the font you chose even the place you put it, it's all very good. I'm very fond of it! :)
I feel like the second is too colorful for angst. The picture of the girl is super well chosen, but it would have been cool to have a black and white poster with red as the only color, so it would definitely pop up! Putting a transparent layer of black on the picture is not a good idea because it darkens the face and skin which makes it less interesting to look at (I think). So my eyes is really drawn to the girl and I kind of forget SJ... If you want something darker I suggest using shadows and contrast instead of all-over 'darkness'. The girl's picture, for example, has a high contrast which makes it dramatic.
For the third poster, the pictures are very well chosen. ^^ I really like Siwon's. You really did well, especially if you had to cut it away from the background. O.O Then again, I feel like the colors are too diversified, given that skin is a mix of red, yellow and white, and not at all green (which is why CG screens are usually green) so it's slightly weird to have both green-blue (cold colors) and skin + Eunhyuk's hair (warm colors, even Donghae's hair is warm...). I think you should mostly stick to one color, one pop of color or voluntarily have two colors that battles each other (complementary colors, maybe). I really dig the background image/texture, though. It's well chosen and totally works with the triangular composition of the foreground.