It's possible the impression share loss due to rank includes losing out on impressions that the campaign is eligible for but are very broad so you would not want to show for them anyway.
Yes. But we currently don't recommend adding product ratings to ads.
What can we do to reduce our CPC?
It is likely that LinkedIn campaigns to warm leads (aka remarketing) could be a good fit, but LinkedIn campaigns to cold leads is only a good fit for a few narrow industries.
Wait for at least 14 days (plus your conversion lag) to view accurate and complete performance reporting