Recolors:
A little work on the outlines.
Splice:
Nidoking's head is WAY too big for Blaziken's body, same with the tail. He needs some more meat if it's to support.
The Patchirisu's head is... interesting.
All the other splices are interesting, but you might want to avoid the same thing with the Nidoking, such a large head for a small body. They don't add up sometimes.
Trainers:
Milly's head is quite flat. :3 She's got a skull beyond that forehead!
That horse fakemon is cute, but it's not to the standard of Pokemon sprites. Like the splices, that teeny body won't support the big head, and you might want to add a big of black into the outline. Just look at a few other sprites for reference.
Overall you've got a lot of creativity and technical skills, but they're is always room to improve! ;D