Hi William,
At the moment we haven't created a badge criteria that is dependent on earning other badges. It's definitely something that we'd like to do though and it should be fairly straightforward as criteria are designed to be extended. You could definitely create a feature bug in the tracker for that one.
The second part (removing the earlier badges when the later ones are achieved) would be more work. I know Mozilla have some plans around badges that "fill up" as you progress so that might meet your needs. Currently that's scheduled to be implemented by Mozilla in version 1.5 (third quarter of this year):
https://github.com/mozilla/openbadges/wiki/Open-Badge-Infrastructure-Roadmap
The only info I can find on the open badges wiki is here:
but it's an old discussion from their wiki that has since been deleted.
Hope that helps,
Simon