Don't add the juice to the boil. The high temps will set the pectins and you will have a beer that will never clear.
The juice will be pasteurized, so you can add it straight to the fermenter with no preparation.
It will add simple sugars, so will not add much flavor. I assume you are making an extract, or partial boil, just use the juice as your make-up water. 1 gallon of juice is somewhere close to 1 lb of table sugar, so get rid of any sugar in your recipe and use a couple of gallons of juice.
Yes, you can bottle with it. Use about half a pint per gallon (2 to 2.5 pints for 5 gallons) in place of priming sugar. If you really want to do it right, measure the gravity before use. 1.046 would mean 1 gallon equals 1 lb of table sugar (or half a pint = 1 ozs of sugar). Using a refractometer would waste none, using an hydrometer would only use about 5 ozs (and then you drink it).
Just make sure the juice doesn't have any preservatives that would halt the yeast activity (ascorbic, citric, and malic acids are OK)