I saw a post that talks about label offsets, but that was in 1.7. I did some internet research with no success. Is there a way to apply a buffer area so that labels from another layer are not placed in the buffer area? Otherwise the only option that I can think of is actually moving all labels that are in conflict manually.
This is not possible as far as I know. It's a rather rare requirement for a label placement algorithm.
It would probably be fastest to rearrange the labels in post processing (Inkscape or other tool).