I don't think making hydraulic oil into a mist is really recommended; it's not healthy to breathe. And it doesn't seem to have kept your stock cool either. Most coolant/lubes are a water-oil emulsion that combine the best features of both substances.
You might think about using a larger cutter to rough out with and coming back with the smaller one to do a finish cut. That would be less stressful for the 6mm cutter.
What CAM software were you using? It doesn't seem to have been very sophisticated if it left prongs standing up in the middle of your pockets. Running a tool into a sharp corner can often break it, if the software doesn't recognize that condition and treat it as a special case.