In summary, the following three things must happen in order for the Seahawks to make the playoffs (if the Rams clinch the division by winning at least one of their remaining two games):
#1 The Seahawks must beat Dallas and Arizona. Duh.
#2 Detroit must lose to Cincinnati and/or Green Bay.
#3 Atlanta, New Orleans, OR Carolina loses its remaining two games.
Because it's more likely that Atlanta would lose at home to Carolina than it is for New Orleans to lose at Tampa Bay, Seahawks fans should probably hope for the Saints to beat the Falcons.
So this weekend, in addition to rooting for a Seahawks victory, root for (1) Detroit to lose at Cincinnati, (2) Carolina to lose to Tampa Bay, and (3) Atlanta to lose to New Orleans. If all four of these things happen on Sunday, then a Seahawks victory over Arizona would be all we would need next week to secure a playoff spot. The Seahawks would essentially control their own destiny to the playoffs if these games went our way.
The Detroit/Carolina/Atlanta games are all on Sunday starting at 10 a.m. PST, so fingers crossed on those. Seahawks cannot be eliminated from playoff contention if they beat Dallas.