Really just put that out there for the OP to see the 3 main tumbling passes. Obviously the skills you listed are backwards. I have no idea what that adds to the SV or what would happen if they were left out. Perhaps someone with greater knowledge in that area could explain.
There is a composition deduction if there is no backward salto. It's minor, but it's there. This fulfills the backward requirement, but doesn't really add anything in the way of Start value to the routine. Both of the skills are valued as "A"s (which are the easiest in the code).
My daughter had a teammate who would not tumble backwards. She qualified to Easterns with no back tumbling on beam, and I think floor as well (but not positive). She actually won beam a lot during the season, too.