You'll need at least a 25mm diameter cutter, possibly bigger, to get the 7.5mm step and to finish the flat in one pass.
I would make sure your Bridgeport is trammed as well as you can. I'd also cut both sides leaving the odd 0.1mm and then clean up to the finished dimension without touching the Z-axis. When you rough it out, leave something on the flats to allow cleaning up with the dovetail cutter.
I wouldn't worry too much about the sharp corners. My dovetail cutters all have the sharp corners either stoned or ground off. The mating dovetails (nearly) always have flats instead of points.
Cheers.
Phil.