Hi Ben,

1. We don't yet have an established concept or property URI for QC state fields on anything other than datasets. I'll open a 10.3 issue to establish one, even if we don't do anything special with it yet, so that at least we can tag fields for use in future releases.

https://www.labkey.org/issues/home/Developer/issues/details.view?issueId=10644

2. Adding built-in buttons only works for buttons that are already exposed on the specific button bar. It doesn't let you add buttons from another place in the UI. So, you won't be able to easily add the QC state button from datasets and apply it to assays.

Thanks,
Josh