Every town will have weapons, sometimes the same as the previous ones, sometiems not. Once you hit the end of the game there will be a place that has most of the good stuff, just not all of it. As I said, I found Hastega in a backwater village north of Rabanastre. So the best things are not found in all of the same place.

The Golden Amulet, I cannot remember where I found that accessory, but I am pretty sure that you can find it anywhere you want these days. Giza Plains village might have it or the Mt. Bur might.

Experience, I am not too clear how it works out, know that I have switch people around before, though they did not deal any damage. I think the people that are in the party when the exp is awarded gets the exp. Considering how fast it all happens, I really do not think switching them in and out is a good idea, it will probably just frustrate you more than anything.