Overall, they're dark for my taste too... given you have IS, you could have exposed a stop or two brighter (assuming you didn't already expose to the right and deliberately reduce the exposes this much). Otherwise good. The soft toy on the head does make for a very long thin shot... I think it would have worked better over his left shoulder, allowing a tighter framing around his face, and placing his eyes in a higher impact position towards the top, rather than around the middle of, the frame.
In the second one, I like the posture but might have put him a touch further right in the frame - as is it's a bit central. I can't help wondering if it wouldn't look better with another 10% in frame at the bottom... seeing half a hand is kind of distracting. The necklace thing being over the design on the T-shirt is also a little distracting... the former on a plain T-shirt, or the latter alone, might work better. The backdrop seems noisy (I know you shot ISO100 so it's weird - maybe JPEG quality factor for posting here, some grain in the backdrop, increased exposure in post-processing...).
Cheers, Tony