Kojuro is the simplest of these, because it's mostly pre-bought components. I'm doing some wig styling, too, but the real challenge will be make-up, because I'm still not much past 'generally passable' and I'd like to work on that more. Gotta do lots of practice...
Toshi has had the bulk of major new experimenting - mostly in the robot-arm, which I'm doing out of eva foam and thermoplastics, but I also had to reweft a wig to get the high ponytail, and this is what I was building my own screenprinting frame for. Lots of discussion on the arm to come, though not tonight. (and lest I forget, art is a commission from the fantastic [Bad username or site: roachpatrol @ tumblr.com"])
Yasusada has some foamwork as well - I'm making a new chestplate, because the one I've been using is actually from a different costume, and is both too big and has the wrong details for this one. The other new stuff is actually going old-school - I'm remaking the arm-guards in sheepskin leather with gold leaf for the crests, and I'm experimenting with traditional Japanese stencil-dyeing techniques and indigo dye to remake the haori. Exciting, if slightly messy!
Each one of these things will probably get it's own post, because I can talk forever about this stuff *g* Hopefully with a bunch of photos, though my documenting is far from thorough