its not that hard to get a track bike legal. nor is it hard to get it legal-ish. you can use aftermarket headlights and taillights. as long as the wiring harness is intact, you can use whatever you want.
when i had a track bike that i rode on the street (which is probably also what i’ll be doing with my 636) i just put a headlight and taillight on it and rode. dont need mirrors or turn signals (I use hand signals, and I have a helmet mirror)