1- Organic produce is ideal under any circumstance whether cleansing or under normal circumstances. If you can't get organic then you do the best you can. Better to continue with non organic than to quit. Press on and do the best you can.
2- Just plain common sense dictates that there is no way in hell that one could even come close to answering this question. The variables are just infinitesimal. Just satisfy yourself if you have improved your diet as you say that the system is not having to detox as much.
3- Absolutely! Yuppy water contains carbon dioxide and that has an acidic effect on the system. This effect is not just when cleasing but at any other time as well. Do some research.