Jh10000 wrote:presume the entirety of this will also apply to fine teas? I drink a lot of delicate Japanese teas where the water is of even greater importance than for espresso and coffee, but if nothing in the water noticeably changes that shouldn't matter.

I know nothing about teas, but I'm pretty sure that would be similar to pourover brews of delicate coffee. The alkalinity is pretty key here. (Brewed coffee, and I expect tea, is far more sensitive to the dulling effect of high alkalinity as compared to espresso coffee). And as stated before, the alkalinity of a bottled water does not change after opening.

Jh10000 wrote:would it make a real difference that the bottles are not stored in a refrigerator, but in a basement?

Any cool dark place is the common recommendation. A fridge, being darker and cooler, might be better but not enough to worry about.

P.S.
FWIW There is a recent YouTube interview of Chahan Yeretzian (SCA and ZHAW coffee scientist): http://www.youtube.com/watch?v=eeP6-PCQeMU . Nothing new if you're familiar with the SCA water publications but maybe worth a listen for some. You can start at 13:32 to just hear the water discussion. He discusses why pH and TDS are not that key compared to alkalinity and hardness, and also the point that water quality is important for espresso machine health, but taste-wise, espresso is much more forgiving than brewed coffee.