A few questions about elderlings, dragons, magic etc. [general spoilers]

[Albertosaurus Rex]

I think many of these things are supposed to be ambiguous. If Hobb revealed everything about the Elderlings, they would lose their mystery, making them less interesting. Of course, it's always fun to speculate.

2. elderling technology
What is the source of the technology? Memory stone? Liquid "skill"? Using skill to change the properties of different materials?

Somewhere in the Tawney Man trilogy, a document is quoted about how various kinds of magic, like Skill, Wit and Hedge Magic fit together. I think a lot of knowledge of magic was lost with Elderling civilization. There might have been magics that the modern inhabitants of the world have never seen.