In your experience, what is the most common autoimmune or other condition associated with symptomatic cryofibrinogenemia? Or is cryofibrinogenemia typically the primary disease process?

Could be either. This disease often starts with skin lesions (ulcers, purple spots, decreased blood flow to fingers/toes). It can either be primary or secondary. When secondary, it's related to cancer, infection (hepatitis c and others), collagen vascular diseases, or vasculitis. Your doctor has to keep all these possibilities in mind. As an oncologist I have seen it as the first sign of cancer.
Usually primary. Cryfibrinogenemia is usually the primary diagnosis and is associated mainly with vascular issues such as raynauds or cutaneous vasculitis.