Undead slaying Paladin

[WarBlade]

I'm keenly interested in ascertaining as to whther or not the "Ghostbuster" effect of Sanctuary against a PI Undead (Ghosts and whatnot) applies only to melee weapons, or is it available to bows/crossbows as well?

Yes, it does apply to missile fire too.

I'm getting conflicting info as to whether the damage increase against Undead via Sanctuary and a bow does occur (or that any sort of +%Damage to Undead modifiers work with bows).

Sanctuary only amped damage to melee attacks in 1.08 and was upgraded to melee and missile weapon attacks in 1.09. Unfortunately the skill description on the character screen is still the old 1.08 version, hence the common confusion. ;)