(Sorry to keep spamming y'all with my wing WIPs, but just in case my ideas might help someone else, I'm posting them here.)

I think I got this figured out now...I'm trying, at least! This diagram shows the internal armature of the fursuit wings, which operate via a string-pulley mechanism (the string being elastic, in this case), something along the lines of these two wings:

[link]
[link]

The foam feathers will be made similar to these, but will be covered in white velvet, and the primaries will pivot on the ends of their wire barbs/quills as they fan out: [link]

Other similar designs:
[link]
[link]
[link]

Anyways, I will probably have to tweak the design further as I actually start making these, and will continue to give updates here, so stay tuned if you're interested!

EDIT: ~lotusii wanted to make these, so I color-coded everything in the image to make it a little more understandable:

Yellow = Fake fur "feathers", stretch fabric and foam padding
Green = Plastic or wooden armature and wing base
Light blue = Wing bolts/screws, wire rods, tubing, pull-tab and hook for string, and other bits of hardware used on the armature
Orange-red = Non-pivoting barbs (aka feather shafts)
Blue-violet = Pivoting barbs (aka feather shafts)
Pink = String pulley for armature and knotted fishing line for feathers

(Hope this helps, Lotusii!)