Please help with my hair dye dilemma!?

You could mix the dyes when you dye your hair so you're only dying it once. Also, the dying over the dye shouldn't hurt if you moisturize your hair properly. The goal is not to fry it. I dye my hair at least once a month and my hair is SUPER healthy, according to my hairdresser. Just buy some leave-in conditioner and have a go at it :]