Dunno if this helps, but once your kingdom allies, there should be a sect of people who oppose the politics of the situation and somehow rail against the PCs.
I would have Nelaria show herself not in any spirit form, but through reflections and the like. A party member sees her face in a pool, watching him. Another party member sees Nelaria in a mirror. They all can hear her, but onl faintly - she never outright appears. And when she DOES cast spells to help the PCs, it's only faintly, for a few seconds, before she vanishes in a wisp. But that's just me.
As for fighter ideas, I've been wanting to run a fight against two or three fighters with Glaives, who set themselves up in such a way that if you go after one, the other two get attacks of opportunity. It'd be a fun (and unusual) fight, if you ask me, while at the same time being absolutely mundane in terms of magical power.