The FAQ we're talking about is silly (although I'm stating it as fact, it still is of course only my opinion), but I am not in any way saying that this means it should be ignored- it would be a strawman argument to state I am making that argument. I am saying that taking a silly FAQ and extending its remit way beyond what it's talking about isn't a smart idea at all. This is an entirely rules-based argument: as noted, monstrous characters only follow some of the rules for monsters, and this is justified in the FAQ by saying that they are considered smart enough to resist such magicks. This is as opposed to infantry characters, who follow [all?] the rules for infantry (I know of no exceptions), and so... anything that applies to infantry, applies to them. It is folly to take that other FAQ and apply it to infantry characters as well.
Remember as well, my earlier post proved that it goes the other way around to what you're arguing anyway. Here's the logical chain:
1) Earlier FAQ implies that magic effect on [unit type X] does not apply to characters that are [unit type X]
2) IoN gives all targets D6 wounds back, except models that are [unit type X]
3) Therefore because a Wight King is [unit type X], the rule saying that he only gets 1 wound back isn't valid, and you refer to default rule for IoN, which is
4) Therefore he gets D6 wounds back
5) ...and he'd probably get D6 wounds back even if mounted as well
See, that's the logical progression of applying that FAQ elsewhere- silly, isn't it?

That's why I dispute point (1) as applying to anything beyond monsters.
"What I've been saying all along is that he's a character on foot. Nothing beyond this."
Nothing beyond a character on foot? Why do you specifically choose to ignore the rule telling is he acts as infantry? You can't tell me that I shouldn't ignore FAQs for thinking they're silly (when I wasn't anyway, but that's beside the point), and then ignore actual rules straight from the rulebook that have already been quoted! Characters are the unit type that they are. A character fighting on foot is infantry. That is the true end point of the discussion. A good place to stop, I think?
[The Corpse Cart Lodestone thing is just because if for some reason you think giving a WK back 2 wounds from 1 casting of IoN is dodgy, who knows what else you might think is dodgy? So let's not let dodginess or silliness sway our interpretations of the rules

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