[FH] KraVak predecessors

What's the consensus of the List:
a) have the KraVak been in human-space before?
b) what are KV burial customs, if any?

I'm thinking that it would be more interesting--more "texture", so to
speak--to give those earthlike planets ruins, burial mounds etc--also
having them terraformed by someone else before we got there would
explain why we have so many convenient planets available.