The challenger looks VERY much like the original, come on. Single bar taillight panel, same exact shape, distinctly mopar grille... They even did it in orange with flat black accents.
The first pic you posted as the "challenger" is actually the plymouth 'cuda concept, but since plymouth fell through, they changed the front/grille afterwards to make it a challenger.
Look at lines, not "roofline." 90 percent of muscle cars had the same roofline.
and come on, anyone who has examined a '69 camaro with half a brain will instantly recognize it as a 'camaro..
the deep "V" shaped grille with turned up upper corners,
louvres in front of the rear wheels,
the small round lights in the lower front valence,
'67-68 body creases in the front fenders and doors.
rockers tapered towards the front,
body line lowering towards the back, until the rear quarter, where it goes up again..
I know of no other car that has that line.
the base of the sail panel is tapered towards the middle of the decklid with a little ridge over the rear quarter..
And how does the camaro look like a cadillac? a car with lots of curves compared to a car with none, i don't see how that works.
i could go on..