Another update. I had accidentally installed gnome-tweak-tool on my unity install instead of unity-tweak-tool, which pulled in a bunch of gnome-core stuff. After uninstalling the gnome stuff and reverting my configs to default (i.e. removing everything I did in post #5) my bluetooth headphones seem to be connecting properly again.
Another update. I had accidentally installed gnome-tweak-tool on my unity install instead of unity-tweak-tool, which pulled in a bunch of gnome-core stuff. After uninstalling the gnome stuff and reverting my configs to default (i.e. removing everything I did in post #5) my bluetooth headphones seem to be connecting properly again.