Seat height new Challenger vs 68 Barracuda

Exactly. I would not just 'pop' some modern seats in my 69 Cuda. I would have them recovered in the same basic style / pattern of the 69 buckets for the nostalgic look.

And the right refurb/treatment they are very firm and comfortable! AKA use the wires in the burlap like the original Your 68 Had!