A:AnswerThey do sell the quick release plate separately. When i bought my tripod i looked at the universal replacement plates and they looked the same.
A:AnswerIt is compatible with my Canon t3i. My friend has used it on the lens, but not sure about the camera body. He has the 70-200 and the 300 mm lens. He has used it on a few occasions. i believe all the Canon lens and bodies use the same size mounting screws.