I haven't found anyone that makes aftermarket bodywork except for carbon fiber. Check with CJ Designs.
You can use pretty much and KTM "big bike" front fernder. It mounts the same way. I used an Acerbis supemoto fender on mine and it worked fine.
Fuel tank. You'll need some quick disconnects for the fuel lines. CPC is a common manufacturer for these. The left side of the tank has the horn, fuel pump etc.. You'll need all of that and petclocks if you want to do a real "quick swap."
I wouldn't worry about the light but you could always wire in an "OFF" switch somewhere.
Welcome to Orange!
2013 KTM 1190 Adventure
2007 KTM 950 SE
2004 KTM 450 EXC
1979 Suzuki GS850
1993 Harley Café Project