Re: alkalizing water.

 Logically, we all are mostly acidic and not pH balanced. Cancer thrives in acidic conditions

This is a common myth right up there with the myth that lack of oxygen causes cancer.  The myth is based on the misconception that acidity causes cancer.  But the acidity is the result of the fermentation by cancer cells, it is not the cause. This is why taking alkalinizers has had such as poor success rate treating cancers.

and it is also spreading like wildfire these days. I know our blood cannot be outside of a narrow range on the pH scale.

Which is why the body has so many mechanisms by which it maintains pH.  And just like over acidity (acidosis) is bad so is over alkalinity (alkalosis).  When people try to force their bodies in to an alkaline state they just stress the body more as it now has to work overtime trying to adjust the pH back to normal.

I also know the body will "steal" Alkaline minerals from ANYWHERE in the body to balace the blood pH.

This is not a complete myth, but very misleading.  Again the body has multiple methods to maintain its pH.  The use of minerals from the bones is actually the last resort method for reducing acidity.  Respiration is the primary.  If the blood is too acidic respiration increases to blow off CO2 reducing the acidity.  If the blood is too alkaline respiration decreases to retain CO2, and thus to increase carbonic acid. The pH can also be maintained through bicarbonate, dietary compounds and through elimination or excretion of hydrogen ions by the kidneys.  Again as a last resort the body will use bone minerals.  Being though that true acidosis is so rare this is rarely the case.

Like calcium from bones, making them brittle (osteoporosis). 

Osteoporosis is not an issue with mineral loss from bones.  It is a collagen loss from bone tissue, which prevents proper bone mineralization.  So it really has nothing to do with acidity of the blood.