Skip, the undead pirate, always guards a chest that has the Battle Drums in it. (Anyone confirm this? Maybe I'm just *really* lucky in my four playthroughs, but his chests always have the drums, and at least one other artifact).

no, he doesn't, I did not get that item from him or the chests he guarded

Items are random

I know this is true in general, but I have literally failed to not get that item there, and at least one other, from those chests. Since some chests can have specific loot (Like in the cave in bolo) I am still somewhat curious to test this a bit more thoroughly.

I have played it 2 times and got completly diferent stuff

I've never gotten the drums there either.

I am maybe wrong, but can't you have the clay bowl at the beginning of KB:AP (via the tutorial or something)?

Clay bowl was in legend i think

Yeah, clay bowl is a possible item to find in this, but not guaranteed. If multiple people claim to not have gotten the drums there, then I guess it was just a statistical oddity.

One more though: Hraro's (Dragon bounty in Tekron) always drops a Dragon Claw.

I've noticed lots of places offer a dragon claw, so the dragon necklace is pretty easy to assemble.