Not quite. You have to deposit a copy of the manuscript in PubMedCentral within a year of publication. Some journals let you deposit the final pdf (or even do it for you). Others restrict you to an unformatted "final draft" (i.e., the last thing you submitted to the journal).

However, this is still tagged with the source journal, so it doesn't really get you around the career-related issues.

Public Access guidelines: https://publicaccess.nih.gov/policy.htm

Open, but not immediately, I believe. Journals have an embargo period of 1-3 years, and after that you can put the accepted paper on a free repository. Your manuscript can usually be posted for free as soon as you want.

It is, but it's after a time. It's not actually weakly enforced - we've been told we can't take credit for publications on grant reports if they're not in PMC.

Don't you need to include the PMC ID number for each paper on the progress report/renewal? I vaguely remember doing something like this for our last one....

Yep - you need the ID number, and if its not there, it doesn't count.

It's solved by "publishing" it in an open access repository - so the data is available to public, but all the ratings and citations and relevant rankings go to the closed access journal where you initially published it.

yes but it's only weakly enforced,and I believe there's an embargo peroid