I find this a fascinating subject. -- Someone wanting to drink coffee on one of these fasts and still consider it a water fast.
The obvious question to me is - is your addiction such that this is a justified way to not part with your daily dose of caffeine?
I can tell from what your stating regarding coffee that you consider that coffee is actually giving you energy.
There is no energy to be obtained from coffee or those gimmicky "energy" drinks.
What you feel in the body as a result of drinking either of these is your bodies reaction to having to handling the stimulant substances in each.
In other words the "energy" you feel is what is already in the body and the stimulant is fact draining it.
I wish you luck with your fasting. You may want to re-consider parts of it.
There are a lot of very well informed people on this forum that can be of assistance.