I think you've done very good on all of those! The only thing that I can see immediately is that there seems to be a bit too much texture shining through the shadowed parts of 'Keith's' wings. Less light in = less light reflected so any texture in the shadow should be very slightly visible or not visible at all. The same applies to the highlighted parts ofc, as the amount of light in swamps out small value variations as it's reflected, but you seem to have that under control already. I always look at your works as soon as I see them posted on dA btw, it's just that I'm really bad at leaving spontaneous comments