I think we can pretty much ignore paladin spells, here. If he's already got "a few" levels in bard, then he's not going to gain any paladin casting at all 4+fewth level, and by that point, a handful of first-level spells really aren't going to make much difference. About all that the paladin levels are going to get him, spell-wise, is access to some wands without needing to roll UMD for them. So I don't think there's any sense worrying about Wis.

That raises another point, incidentally: With both arcane and divine class spell lists, there aren't all that many spells which he'd need UMD for. So that frees up a skill slot.