This issue most likely has to do with change introduced in shaders in Unity 5.5, which we used to build the latest hotfix, and should be fixed in our next one.
I've got the same graphics card in my mac, and I have been able to render the minimap, but on my windows partition. Next time I'm testing mac build I'll try to figure this out.
Campfires are currently broken. They will be fixed in the next update, tomorrow.