So instead of searching how to unlink NNID on CFW, you just did what Nintendo did on normal systems... Good job.
Either way, for Luma just go to Luma's github, releases and download the newest one, putting boot.3dsx on root of the SD card.
As for FBI, once you have Luma working, download FBI.3dsx and put it on SD card in 3ds folder, and also grab FBI.cia and put it in cia folder. Then, copied from 3ds.guide
- Launch the Download Play application (this icon
- Press (L) + (Down) + (Select) at the same time to open the Rosalina menu
- Select “Miscellaneous options”
- Select “Switch the hb. title to the current app.”
- Press (B) to continue
- Press (B) to return to the Rosalina main menu
- Press (B) to exit the Rosalina menu
- Press (Home), then close Download Play
- Launch the Download Play application
- Your device should load the Homebrew Launcher
Once you have homebrew launcher working, launch FBI from there and use it to install the CIA of FBI so it's on home menu
EDIT: I forgot, you also need boot.3dsx on root of your SD card from
https://github.com/fincs/new-hbmenu/releases/tag/v2.0.0