Would pancreatitius show on a abnominal CT w/o contrast but with barium shake?

Pancreatitis. It can. You can see inflammatory changes around the pancreas. It would be difficult to assess for necrosis of pancreatic tissue which is seen in severe pancreatitis without IV contrast though.
Depends. The most sensitive test for pancreatitis is a blood test (serum lipase). If that test is negative, pancreatitis is essentially excluded. Ct scan can show abnormalities even with very mild pancreatitis. Nevertheless, when pancreatitis is mild, the ct is sometimes normal.