1. Would be a new feature, not really a bug. There have been multiple attempts to resolve which have all failed. DEPs exist to address this shortcoming.
2. Yep. Still a crappy situation to be in, but one that's also tricky to solve due to not being able to control the joins across multi-valued relationships.
1. multi-column primary key.
2. annotate several counts for some query correctly.
that what I remember for now.