Lt. badges one first, cause it's short. For the placard thing, use a piece from a birdhouse kit like the kind you buy for kids to put together (it should be about the right size adn shape and you won't have to cut a board to size) and do the squad number and flowerthingy with a black permanent marker or (if you have access to such a thing) a woodburning kit.
Now, for the sandals:
*Caution! This is written like a recipe! Read the whole thing through once before you start to make sure you have everything you're going to need.*
You will need:
Reed placemats/floor mats made from small reeds
Heavy-duty glue such as rubber cement or shoe glue
Canvas or leather strips
Medium-gage wire (or two coat hangers that can be sacrificed to a good cause)
Paper large enough to trace your foot plus four inches
Awl or screwdriver
Dark coloured marker
Purchase reasonably flexible reed mats (i.e.: placemats), enough to make two soles for each sandal (that's four separate pieces once you cut them out) or more if your mats are particularly thin. Make a paper template from your foot (remember to go up the heel) and lay it on the mat so that the reeds are widthwise to your foot. Trace around the stencil, making a nice thick line. I don't recommend cutting more than two layers at once, so take that into account when tracing your patterns. Once your pattern is laid out and BEFORE you cut, take a look to see if your mat is likely to fall apart once you cut it. If the binding threads are too far apart or if you're working with woven reeds, you should strengthen the edges by sewing them (if it won't kill your machine) or using glue over your tracing lines. Once you're ready, cut out your (minimum) four pieces of sole and set them aside.
For the lacing, I recommend rawhide laces if you can get them, since rawhide is both strong and light, and won't stretch out with wear. If you can't find rawhide, suede laces are your next best bet. The kind good hiking boots use are sturdy but flexible. I don't recommend leather lacing because it tends to be less flexible and much more difficult to tie. If rawhide or suede are out of your price range/unavailable/morally objectionable to you, then I'd say go for a sturdy 1/4" diameter twine, one that isn't too fluffy (jute has a tendency to end up looking like a fuzzy caterpillar after being rolled back and forth a bit) and isn't too stiff. You're going to be walking around in these things, you don't want something that's going to cut into your feet after a while.
Once you have your lacing material ready, cut the appropriate lengths for the "body" of the sandal. Make sure to allow for at least an inch more than what's going to show when you're done to anchor them, and loop them for lacing then bind them together below the loop with a heavy colour-matching thread. Next, pick which of your sole pieces you're going to use for the top. Place it on the ground and put your bare foot on it in the position like you're wearing it. Use a felt pen to mark the places for each of the supports, and if at all possible, try to put them between reeds. If you're using more than two layers total for your sandals, this is a good place to use two instead of just one. It'll give you more protection from the inevitable slight bulges which come from anchoring the supports (those who will be wearing authentic tabi should also consider that the bottoms of the tabi are thicker and more cushioned than our socks and so provide more protection all on their own). Using an awl or screwdriver or other blunt object, push the bottom of the supports through the top layer of the sandal and glue them to it as flat as you can make them.
When this stage is done, glue all pieces of the soles together. The next materials you'll need are heavy canvas (something from an outdoors store rather than a regular fabric store if you have one in your area, since this part is going to get a lot of wear) or leather, and medium-weight wire. Clothes hanger wire is about the right stiffness although a small spool of wire would be better than a clothes hanger since the existing bends could be a hassle. If money's an issue, though, save here and sacrifice a pair! Bend the wire around the outside of the sandal and tack it into place (some strategically placed duct tape ought to do the trick). Cut two strips of the canvas or leather long enough to go around the sandal with a slight overlap and wide enough to have a half-inch border top and bottom. If you're using canvas, don't forget to allow some extra to be tucked under to give you a neat edge. You can glue this down or sew it down, but if you can manage it, I'd do both. You are making footwear, after all, and if you're taking the time to do something "authentic" it's worth taking the time to make sure it's not going to just fall apart after one or two days. Cons are hard on the feet and the footwear!
Once this is done and well dried, bend the heel guards up into place (having your feet in the sandals will probably help with this), lace the shoes up and you're ready to run around killing hollows... with appropriately peacebonded zanpakuto, of course!
One final thought. If you're in need of extra comfort, you might consider adding rubber soles to the bottoms of your sandals. I'm not entirely sure where you'd find them, but maybe a shoe store or cobbler. I know you can buy non-slip adhesive rubber pieces for women's high-heeled pumps, so something like that but larger might give better traction and more cushioning to your feet.
If anyone has any other suggestions to add I'd be happy to hear them! Or if you make these before I do let me know how they turn out!