Adding too many oils won't cause problems, but it might make it more difficult to figure out which one is the wrong oil for you if there is a problem. Many love jojoba, but my skin hates it! What I would suggest is try just castor and one other oil to begin with, then start adding the others slowly to see how your skin reacts.
Be very careful with the peppermint EO!!!! (Actually any EO) Don't add more then 12 drops total to 1 oz of oils. 1 oz = 2 tablespoons. Lavender or tea tree oils are nice for problem skin.