Please describe the workflow that is not working for you and tell us something about your system. Dynamic Link should work fine. A google search for C300 Adobe Workflow brings up articles from Able Cine on importing and several other resources indicating what to do to make things work properly and avoid crashes.
Is your CC up to date? Have you checked the first 3 resources from a Google search?
Yes, After Effects CC (12.0) can use Canon XF files, including those from a C300 camera.