First off, let me say I love the idea of adding the White Hand; really looking forward to it.
However, I don't like the idea of Desperate Hope at all. Mulcarn may be the least evil god, but he is certainly still evil. I don't think that just because you oppose the forces of Agares, you become neutral. Mulcarn is a viable alternative to Hyborem, but he's still recreating the death and suffering of the Age of Ice.
Which isn't to say that I don't think he should oppose the AV. I personally think it's a more interesting story if you have evil splitting between the Ashen Veil and White Hand. In Desperate Hope, you've got the White Hand joining with neutral and good to oppose evil. If you don't add it, you get AV fighting an alliance of good and neutral nations, with the White Hand being even more united/organized and fighting both of them.*
*If I remember correctly, there is no hell version of snow/tundra. I'm not sure if it can still count towards that 90% hell-spread AV needs, though. If it doesn't, then you have an automatic conflict between AV and snow-spreading White Hand (who'd be making it much harder for AV to get their 90% hell coverage). On the other hand, neutral and good won't like 'em cause they're evil. Also, the whole breaking-the-compact-again thing probably won't sit well with anyone, but that's more lore and less game-mechanics.