I am personally not a fan of Samyang lenses so the Xeens would be out of question unless I would have change to intensively test just the particular lens I'd been buying to ensure that it would not have manufacturing defects and it would be optically as intended. I have just had too many problems with every samyang lenses I've been using, especially mechanical problems, so it would need quite much work that I would trust the Xeens for any bigger project. the t-stops are promising but the mechanics and coatings matter more in cine work.
For me the CP2's would be the obvious choice I think if I would not need wide angles much. their wides are not that fast and you still need to stop these down about one stop so it would be a bit limiting to use the below 25mm focal lenghts. the mechanics are good and one could trust them more than the samyang ones I think. CP3's may be over the price range.
I would love to test the Schneider Xeon FF primes some time, they could still fit the price range you are after and could maybe be better for your use than the CP2's look-wise.
I kinda like the look of most of Sigma stills lenses, they could work nicely in PL mount if the mechanics are fine. however, if you are mainly using digital cameras and the budget is an issue, you could be much happier with EF or Nikon mount lenses and just changing the camera mount when needed. it would also be much cheaper than trying to get everything in PL, especially if you are shooting lots of special shots and macro where you can benefit from much cheaper special lenses and adapters. calibration is a problem with "cine" stills lenses with for example EF and Nikon mounts and PL is much sturdier mount though