Only if they retain their original shape. The point is not that any wave is a soliton, but a soliton never changes shape as it moves (through time, a medium, or whatever). The soliton can decrease in amplitude, and expand in width, but otherwise remains the same.
A pure, single Gaussian hump is the soliton for homogenous linear media. If you create an audible with the spectral shape of a Gaussian (and therefore also the time shape), it might get quieter as it moves across the room, and longer, but will still "sound" the same.
I believe so, although the way I usually think about Solitons is like a single packet.. so just one cycle of a wave. Continuous sound could probably be thought of as a continuous stream of solitons (I think ppl call them phonons when it's sound though). I haven't studied PDEs nor solitons in a formal way I just love playing with them. Gray Scott with History and Wave (a formula I contributed to Gollygang/Ready) supports many fascinating soliton behaviours. Here's 25mins of one of the strangest parameter settings I've found:
A pure, single Gaussian hump is the soliton for homogenous linear media. If you create an audible with the spectral shape of a Gaussian (and therefore also the time shape), it might get quieter as it moves across the room, and longer, but will still "sound" the same.