Their Roles change everytime (except for Snowball's):
1st animation - Smoke is the Final Boss, Dust doesn't yet exist.
2nd animation - Dust is the Final Boss, Smoke doesn't apear.
3rd animation - Can´t remember who is the Boss but Dust is a bad guy, Smoke helps Snowball.
4th animation - The Boss is a Guy who's name I don't know, Ruby helps Snowball, Smoke and Dust don't apear(I think).
Hope it was Helpful!