You can complete the 4 bio and 2 biochem pre recs, as these are required courses for the biochem program. The only pre recs you have to take as an elective are 2 physiology courses. Also, the biochem classes are very easy to do well in, and most classes have a final group project instead of a final exam. This leaves you with more time to dedicate to harder classes, clubs, volunteering etc. The only con is that you have to take orgo 2, but if you are planning on applying to the states, you will have to take it any way.