Hi Sundance,
When I unfroze my ATPL (UK JAR) about 18 months ago, the CAA requested a letter from my line manager on company paper stating all the hours in my log book are true and correct. They did exactly that and my licence was issued with no probs. I did not have any individual captains signatures.
As far as logging hours, all PNF is logged P2, all PF is logged P1/S. Tou can't log P1 until your the skipper.
Hope this helps
REAC