The first two examples relate to codecs that are not installed by default. Most probably they should not be available for installation at all, but then it's the way that packages are available in the "universe" repository.

The third example is a valid issue, and got fixed. Apport is important to receive feedback from crashes. It is not enabled by default if you use the final versions of the installation ISOs. It is enabled only in the dev versions of Ubuntu.

Bug bounties would be interesting. Should they be monetary or should be something else (nice t-shirt). The issue with monetary bug bounties is that they make sense to money-making software and services.