Here’s some suggestions. These are food for thought but may not be the most ideal way to go.
Hopefully someone else will chime in and correct anything that looks like bad advice.
Put at least an Nvidia GTX-680 in the Hackintosh or if you can afford it pick up a GTX-980 or 980Ti on eBay and then you will have really good CUDA Rendering. I’ve seen the 980’s go for $150US or less. Note: you would then need to install the Nvidia Web Drivers that you can find on MacVidCards.com and also the CUDA Drivers for Mac for CUDA Support. As far as a Dongle goes I don’t think you will need one but Mac’s revert to a 1280 x 1024 Frame size without one which may be ok but with a Dongle you could use higher res settings like say 1920×1080 or higher.
Here’s links to a couple that I found through a quick google search.
https://www.ebay.com/itm/HDMI-dummy-plug-4K-DDC-E-EDID-emulator-fake-display-headless-slim-DVI-/161265341755
https://www.amazon.com/1920×1200-Emulator-mining-Headless-server/dp/B00TT97I44
I used a Dongle for awhile but I found it to be a pain constantly having to remote desktop into my secondary machine.
I ended up finding a Benq GW2270 21.5″ Monitor for $70US and this is so much better than the Dongle, Remote Desktop thing.
As far as the Project goes never open the same project on two machines if it’s on DropBox.
This should be done through Creative Cloud because it’s set up to handle project collaboration.
Lastly your media. You will need to share the Media and that can be a bit of a problem. You could use a network share but that can cause some problems like poor render or playback performance. I’ve also run into glitches or crashes especially with consumer GigaBit Switches. Some kind of a NAS or Small SAN would be ideal but may blow the budget. We use a large SAN and my best advice on any shared solution is to mount the Media Volume(s) in Read only on the Render System so it can’t make changes to these Volume(s). You can run into some fairly major issues and crashes if they are R/W on both systems sometimes. The down side of this is that you will have to render everything on your Hackintosh to another Volume and every time new media is added to the Media Volume(s) you will have to Unmount and Remount or Refresh it/them for the media to show up on the read only Volume(s).
Side note: I run Mac Pro 5,1’s with PC Versions of the GTX-980Ti’s in each machine for two reasons. Nvidia doesn’t make Mac Versions past the GTX-680 and it’s about $250US all in to get a card flashed with the Mac EFI. That’s a lot of cash just to be able to see the Grey Boot Screen. I want to but haven’t done the Hackintosh thing yet so I’m not quite sure how they handle the PC EFI on a Video Card so that your Monitor(s) come up properly. If you go to a higher end Nvidia PC Version and the monitors don’t come up on your Hackintosh drop me a line and I can share my tricks to get it/them working.
Thanks for reading this NOVEL and I hope this helps.