Yes, but maybe she'd bank on no longer needing those powers to complete her plan.
I thought Hel was explicitly playing strictly by the book to shame the other gods into honouring the agreement. If she starts breaking the rules, there's no reason for them to honour the agreement either and she might lose all those souls.
Indeed. For example, the compact is what allows clerics to cast their full range of spells. Without it,
domain restrictions become much more...ah, restrictive. Given that the entire plan hinges on Durkula being able to dominate the voting elders, if Domination happens to fall under another god's portfolio (f'rex, the manipulative Loki), losing it would be major potential crimp in their game plan. Moreover, if the rules of the game get thrown out, she may have to worry about the original vote itself being disqualified. Several of the gods who happened to vote alongside her only did so as a protest vote, as Hermod indicated, or not knowing the full consequences of the act; the "
no backsies" rule could easily be next on the chopping block if the compact falls apart, and if that happens, she loses her own voting base. The plan only works because the rules benefit her right now. If she breaks the rules, they get to do the same gratis. If they break the rules first, they get to fall apart in recrimination between the Lawful and Chaotic wings, which keeps them busy while she gets on with the plan.
It helps that the older links above inspired me to reread the whole arc quickly; I had forgotten quite a bit of this in the interim.
EDIT: Actually, scratch that specific spell example. I just checked since it was bothering me, and Dominate Person is not a Cleric spell. It's a supernatural ability innate to all vampires and is thus unaffected by the compact. Ah, well, the voting point still stands.