Umhh.. I know I'm late by I don't know how long, but I wanted to clarify a bit of everything =
1) To compile FNF for Switch, you need the Nintendo Switch DevKit.
Ninjamuffin has confirmed that a partner, having the devkit because he is a developer, has tested it, and fixed many bugs, such as audio. But it was never released because releasing games on Switch is more than a complicated undertaking. The existence of the "Lime-Build-Switch" (.bat) file is due to the fact that this colleague created a FORK of FNF, and worked on it privately
The FNF Nintendo Switch porter is him (he coded the Switch Support for FNF):
https://github.com/BrandyBuizel
2) Funkin-Rewritten is a re-write of FNF in the (.lua) engine. you can compile it because it uses DevKitArm (a set of Homebrew DevKits recreated by fans), and you can play it through Nintendo Switch with Homebrew
