I'm running Yosemite on my iMac and EOS Utility 3.0.1 is working fine for me. So is DPP 4.0.2. Camera is a 5D Mark III.
Edit: Just installed DPP 4.1 and EOS Utility 3.1, and they work fine with Yosemite too. The major changes on these versions is support of the new Canon 7D Mark II.
FWIW, I contacted Canon regarding the lack of update on their Print Studio Pro plugin for Lightroom. They have no expected ETA for any of their updates to Yosemite.
Mind you - Yosemite has been available to developers since June. Kinda makes you wonder what Canon's excuse is.
Consider a digital asset manager such as Aperture (really too late in its life cycle) or Lightroom. There some other DAMs in the market; however, they do not have an integrated with plugins like Photoshop, Pixelmatr, Perfect Photo Suite, or the Nik Collection.
This doesn't answer your question, but some suggestions:
You could use Image Capture (if you have it), or Adobe Bridge (bundled with any adobe software).
Bridge is a browser. You mean DNG Converter. But if you're going to use Lightroom, just import the .CR files directly into LR. -You'll save a step and avoid conversion shenanigans.
It looks like Canon has released updated software for Yosemite. They just updated Photo Studio Pro (Lr plugin for their printers).
... but it took three months for Canon to update their software.
Plus all those those months they had access to the beta versions of OS X 10.10.