Yes, gaited saddles are different because many gaited horses do have the need of more shoulder freedom. If they didn't then there wouldn't be any such thing as a gaited saddle.
However, not all gaited horses need gaited saddles, it all depends on their individual conformation.
As for the bit thing, I personally believe that the whole "gaited bit" thing is nothing but a load of hooey. A bit is a bit is a bit. The different types (snaffle, curb, spade, etc) should be separated by the training level of the horse, not the breed.
There are a lot of things that I don't understand about the gaited world and their choice of bits is one of them. I have heard this from a gaited horse person and it completely flabbergasted me. They said that this bit was a nice "starter" bit for a young/green horse.
In my world, you'd get shunned for using that type of bit on any horse, let alone a young/green one.
What really bothers me is that if you google "walking horse bit", you come up with a bunch of pictures that look almost like medieval torture devices. Their explanation is that "it helps them gait better", but I call BS on that too. How in the world would having a double twisted wire or chain mouth bit with 10 inch shanks help a horse gait better?
LOL, anyway, that's my rant for the day