First: I don't know what happened, but that isn't my post up there!!
Here is what I think may have happened:
Believing that TPTB like to recycle ideas around and tie up loose ends, I think possibly single mom Ella (who came out of the limo at the same # as single dad Jason

) was supposed to have come out of that 2-1 and been in the F4 slot the same as Jason was in DeAnna's season when Graham was F1. When Graham left, Jason went to F2.
When F1 Ali left, Ella would have move up, and this time we would have had the single parent win the F1 (where Jason came out F2).
Vienna was always supposed to have been the drama role like Tanner, Robin, Marshanna, etc. However, Jake emotionally bonded with Vienna, and he did not emotionally bond with Ella. Therefore, he cut Ella, and Vienna took that F4 slot that Ella would have had.
When Ali left, Vienna took over the F1 slot that I think the producers wanted Ella to have to make the single parent angle go full circle.