For the necklace I think you're in luck, those beads are all either readily available to buy or easy to make. For the pearls you could just buy some actual pearl beads,
but if you can't find them big enough (which admittedly could be a problem) you can easily make beads out of clay. FIMO has a couple nice "effect
" options that come with some sparkle already, or you could also use some gloss gel
on top of a normal or sparkly clay.
I'll admit I assumed you could just buy a magatama bead, and you can, but not in the right color or size. I think that will also be a really easy shape to make yourself using the materials I already listed.
Regarding the hair beads I've never put something like that in my own hair or wigs, but I don't see why a regular bead wouldn't work. Something like this
could be what you're looking for, and just paint and varnish as you like. There's also hair beads you can buy on Etsy, mostly meant for dreads but they should work here I'd imagine. It'll take some digging on their to find the right style though, most were very different shapes or colors.