Zac:
I can't help with the parts, But I just love your Avatar. I was gonna use My Ferret but couldn't catch her for photos. Now concerning the parts. Can you carve wood?-Like Basswood? If so carve the missing parts out of little blocks. Once you've achieved the right contour and fit ( Just a wee smaller than the actual part.) Polish the surface and glaze it with Clear Acrylic.
Take some sheet plastic and stick the blocks to a cookie sheet. Take the largest piece and carefully lay it on the Form, Holding it in an out of the way corner. Then use the Hot setting on a hair dryer until the part is shaped over the form. As it forms, let it go. It will sag over the form.
Do this with all those parts. Cut to fit and install. That's cheaper than a whole kit and will give you the satisfaction of fixing it yourself. Plus, You will have learned a new skill!