It’s probably too late, but since my opinion is basically just agreeing with eternal, that shouldn’t be a problem.
If it’s possible to do, a good bike shop will be able to make the brake light work with the pedal. Obviously make sure that the rear brake works, and that it can hold the bike. You can fix the wiring issue later. When I got my bike, I had to depress the pedal further than I like for the light to come on, so I adjusted it so that it would come on earlier.
Lets see some pictures once you get it.