You'd want the CC 2014.1 download for anything 2014 or newer.
Are you coming from After Effects? For that particular output, I would render from the AE Render Queue, modifing the Lossless with Alpha Render Settings template to use Apple ProRes 4444 insetead of Animation. The 16-bit color depth starts with the AE project settings; however, you'll see a pop-up menu for Color Depth in the Render Settings as well. I'm not in front of AE at the moment, but will say "Trillions of Colors" and you'll also want to double-check that the pop-up menu is set to "RGB + Alpha".
That said, the AME ProRes presets for 2014 or newer have a 4444 with Alpha preset.