Is there any way to move all the existing item costs en masse to the new 2 systems.
Ouch, no, not at the moment. But I could probably manually do it quickly for you using the item names (Felheart, Nightslayer, etc).
Also we somehow have all the ZG loot initialized in our old DKP even though ZG was not a DKP zone for us. Is there any way to "uninitialize" a zone and it's bosses? I couldnt figure it out and just want to clean up everything before we start using the 2 new DKP point systems. At some point long ago we did have ZG initialized in a different DKP system, but this current one was used for only MC / BWL / Ony etc... But upon creation we saw all the ZG bosses and loot tables. I want to avoid duplicating that if its possible.
If you want to delete the items, you'll just have to do them one at a time, right now. I've had plans for a "mass deleter" but it's not ready yet.
As for deleting Destinations, check out the "Destination Merger"