Candy would be the best one to answer questions about her diet plan. She is on frequently, so I'm sure she'll be able to help answer those substitution questions you have. I'm glad you are asking about it here though, some people just alter recipes and substitute, and that changes the nutritional values, so asking if it's possible and how is a great thing, good job!
As for "Green Juice" There is a specific juice or juice type that falls into that category, I'm again sorry I'm not knowledgeable on those either.
In the meantime, have you read through Candy's website thoroughly? I ask because she' really good at explaining things and relating information. She has done a terrific job in research and putting much time into diet's nutritional structure/balances and may have some answers in form of recommendations on her website. If not, I'm sure she'll be on sometime today.