As to front plates, I'm in favor of them. I think a car looks naked without one, so I was glad when mine came in and I could get the bracket installed.
As to the electrical problems, six words: You should have bought an SE (well, five words and one acronym).
The fewer items you have, the less can go wrong.
As to the taillights, what is the apparent problem? Did the dealer say what's up with that? Is it all Challengers or just specific models, like those that are overloaded with electronic doo-dads?