I am unable to get this to show up for wow classic in twitch.

Possibly time to review this? I've seen several addons that are linked to both retail and classic.

I know they announced that they would be adding classic and bcc support, but have they officially added it yet? I'm basically just waiting on that to go through once and for all

I'm not sure but it looks like it to me. See the sidebar here for example https://www.curseforge.com/wow/addons/plater-nameplates

Yes, it is not listed for WoW classic in twitch because Curseforge has serious breakages when you try to have the same add-on linked for both retail and classic. Until Curseforge fixes their system, I cannot fix this.