I'm so sorry you're having such a rough go of it, possum. The insomnia sounds hellish. I'm thinking that the 'hallucinations' are most probably the result of exhaustion. A cruel twist, because those kinds of mentally stimulating hallucinatory experiences can keep you from falling asleep.
I had rotten insomnia last night...sleep since coming off Seroquel is unpredictable.
I think your decision to wait a bit on dropping the Seroquel is a good one.