Various rule questions

I’m reading through the rules, and I have some questions that probably won’t be relevant to me any time soon:

Does Dispel Magic affect unused disks? (I suspect no, and that “Disk spells are active while you have the disk” doesn’t apply if you haven’t cast the spell yet.)

How does Dispel Magic affect magical items carried by the target?

Each purchase of Spirit Shard gives you more disks. Is the spell itself infinite use, so long as you have disks?

Dispel magic doesn’t affect uncast disks.

Dispel Magic doesn’t affect items beyond ending active duration effects they generated. So if you have an item that let you cast 10 spirit darts in the next minute after activating it, and you’ve activated it, I’d expect the dispel to end that effect (stopping you from casting more darts from it within the next minute). But if you’d not activated it yet, there would be nothing stopping you from activating it immediately after being hit with a dispel. Dispel Magic is really rare - you’ll likely see "Dispel " if you see any dispel at all. (I honestly can’t recall seeing Dispel Magic cast in the past 5 years, but I’m guessing someone has.)

You need a disk to cast a spirit shard. The disks are transferrable. The ability to cast it is infinite use.

I’m trying to remember the last time I actually heard a “Dispel” call at Witchwood…

I believe it was Leopold vs. the drum spell singing undead by Clover (Dispel Circle)