Anna,
As you have seen,, there is a lot of excellent info here. For the most part,, you have seen the advocy of heavier,, deeper penetrating ammo in the biggest caliber you can get will be the best way to hopefully stop a charging bear. And yes,, the likelyhood of being attacked by any bear is remote,, but a possibility. You already have a couple of guns,, suited to most of your needs,, but the ammo choices are limited. While the 240 grn JSP is better than the lighter bullets you mentioned,, a good hardcast heavier bullet is even better.
I apologize for some of the ruffled feathers comments that have caused folks to stray from the main topic. Including mine. I will say that the wording of Bearbio's initial posting was a bit wrong in how it encompassed everybody east of the Miss. However,, MANY well educated folks do live east,, and are well aware of what it takes to stop a black,, or a griz.
However,, you appear to be totally open to good discussion,, and seem quite prepared for your trip. As for the coach gun,, it's a very fair deal,, but maybe not the best for bear SD purposes. (I'd buy it just because it is a good deal.)
Have a great trip,,, and we expect pics & stories when you return!