I don't night hunt anymore, but I would take the shotgun. A buddy of mine said he missed one with his rifle last week, at night, about 20 feet away. Said he wished he had the shotgun.
Yeah I'd take the shotgun also, don't count on that fiber optic sight, it's nothing more than a bead sight at night. I would give thought to some smaller shot maybe #4 buck, 00 seems a bit much, unless of course you're mad at them for some reason
Don't forget that at night with a shotgun, the tendency is to shoot high. Folks get the muzzle high so they can see the front sight better. I saw an excited fella miss the whole back end of a Chevy Blazer, one time.