Without seeing some example anatomy it's hard to say -- and I wouldn't feel comfortable telling people to work on anatomy when mine is so wonky!
I don't think I've ever made a piece where I've thought, this one is for practicing linework or this one is for anatomy. They've never been separate. There have been some where I've thought, in this piece I'm going to try doing my shading like this, and then I've experimented with that and it's either worked or not.
With linework, one of the things I've noticed is that hesitation punishes you more than inaccuracy. Nothing looks more obvious than an attempt to fix something that wasn't perfect. Do it once, don't worry if it isn't perfect. There are also times when I've ignored precision in anatomy and just focused on speed -- draw things as lively as possible, even if the proportions are wrong. I think for that, you need good linework to carry it off.
These are really nice! I like the cartoon style. I think the work would benefit from cleaner linework.
My workflow is to draw pencil outlines, ink over, then erase. I'm trying to lean less on the pencil for detail and go directly to ink, but that's for the future. Inking is always done very carefully and slowly -- if there's speed, it's at the outline stage.
I use a fine propelling pencil for outlining, and a Rotring Isograph (0.1 mm nib) for inking.