You've got some beautiful designs here!
Have you considered revamping your thumbnail design to be a little bit cleaner and simpler? Also, I highly recommend ditching the LEGO logo, using it in this context would almost certainly violate their Fair Play policy:
See the full legal notice here. I've been keeping an eye on your minifigs for a while now, and I've seen how much you've progressed as an artist. If you study this sorta thing in college and/or university, you might be able to apply for the LEGO Internship program in Billund. It's worth a shot.