You did quite a good job on lightening,placement of renders/stocks are fine but the main problem in every of them is oversharping.It lows the quality of your avatars.I have a feeling you'd tried to use Topaz filter...looking on your second avatar,well not bad but not good either usage of this kind of filter.Blur more backgrounds,more darken shadow parts.
Aww and text is good on the second avatar only,the rest are just mehhh.
You'd better come back next time with the tag or something new ~.O