Great and beautiful artworks, i really likes the fact that you are working with 3d , solid forms and a thumb up for shape designing and proportions as well. For your concern on linework, i am observing that the contours of what you have drawn are already pretty confident. The place where i sees most of the issues in the internal form and details. So i am going to suggest two changes in the way you puts in the details (while still trying to keep your " Style " in mind ) . The two things i would suggest are 1. Implicit and explicit drawing , 2. Detail type, . Starting with the observation and theory, the main issue i sees in your artworks is that you are drawing the whole construction process onto the page. From the simple loomis head, to the kaido's face ( i sees that you added the heavy cheeks of kaido on top ). That's called a " explicit " drawing. I would suggest you to keep more things ( form, perspective lines, etc ) in your mind, but still try draw less ( only important ) on paper. That's "Implicit" drawing. You may think it sounds insane, but you probably are already doing it to some extent when you draws only the visible part of the cross contour and not the other side. You can take this further by imagining most of the cross contour, construction process and drawing only the contours of the form. So simply, try to decrease the number of guidelines you needs to draws. Yiu can achieve this by practicing to imagine most of the perspective lines, and practicing to draw contour manipulation of more complex form without drawing the base form. This should ( with time and practice ) help you get rid of all the lines i marked red on portraits. Next up, for details and texture i am observing that you have covered the whole body of kaido in scales. This is unnecessary. Keeping in mind that animation style lies somewhere in middle of complete implicit ( cartoonism ) and complete explicit ( rendered , realism ), you may want to decrease that. This can be done by drawing only the illusion of detail and not the detail itself. You can use a "Detail grouping" for this. The idea is simple, you groups the details into 3 types, 1. Silhouette details, most impactful and important ones, applied on the contours, 2. Mid-details , weakest impact, applied on the parts which recieves high amount of light the ones you have mistakenly applied on whole body, 3. Shadow details, second most impactful, it occurs on the part where the for, turns away from light, so the texture forms themselves casts a strong shadow. For animation style, i would suggest to still keep some of the mid-details in, but still try to reduce them down, a little and experiment with different ratios for what fits your taste and style.

Awesome design iterations here! I think you're nailing it with the form exaggeration. I would try to limit your detailing to focal areas just like Sam Keith does. If you try to overdetail, you end up losing the form its impact. Keep it up, real good stuff!