MCAT study hours vary with each person, but I would feel safe saying 50 hours per week for ten weeks would be pretty good.
I would never recommend taking the MCAT without Orgo 2 or Biochemistry, but will say that I have seen some students who had not taken biochemistry do well on the MCAT. If you have a good grasp of research methods, then you will be able to get questions on every experiment-centered passage. In the cases I am considering, these students had an exceptional grasp of the chemistry and biology material leading up to biochemistry. A good part of biochemistry is reviewing preceding material, but making it blend and be more applicable. Do you absolutely have to take the MCAT without first taking biochemistry?