If you want to test the idea, you could use the HDTV versions I’ve already uploaded:
Sunset:
https://mega.nz/#!GQlSmS4J!luBluderZeOJglzTX7Qf0mRCm9XL6NfpvjyctQO_4gg
Night:
https://mega.nz/#!2JNmTaYK!F7r_Ozv2KWMkxPJVSXdPquFV6G32ApoA0kL8QDD0GJI
I can render the Blu-ray version of the sunset, but a night version would take time. However, it’s such a short scene that I don’t think fading one into the other would be very realistic.