I use water all the time to clean briar pipes and it works great. And the cost of buying a cheap bottle of vodka for cleaning is infinitesimal. Not sure Everclear works any better. All you are doing is wetting part of the pipe cleaner in most cases and not every time you clean! Now, to each their own, but my 91% isopropyl says: Not Fit For Internal Consumption, so why would I want to get it into my bowl and cake? Plus the vodka stays around longer to do its job and isn't quite so volatile.
As to leaching silicates, I can't confirm that in a search on the matter, but it would seem that again, vodka would be gentler than iso alcohol. I'd like to see some study that shows it actually made a difference. Anything leeched out can usually be put back in.