Hi! I think these look really good! I especially like the top 3-the pony, mouse, and mouse paw. You seem to have a style, something I struggle with and kinda wish I had :) I like it very much. The last drawing, anatomy wise, seems off. the knee on the left leg (left on the paper, not the subject's left) is off, and the lower thigh area on the right one as well.
When you say you find it hard to do a complete drawing in 10 minutes-if you start out with very very simple sketchy lines for everything, that may help? Rather than spend a lot of time on one part of the subject and get really detailed with it, you could do a general sketch of the entire form.