I did the necessary investigating and the deciding tiebreaker between Dallas and Arizona would be record versus common opponents. And that tiebreaker would go to Arizona.So yes, it is true for the NFC. If Dallas hangs on tonight, it ensures Dallas/Philly and GB/AZ matchups the next 2 weeks so long as Minnesota doesn't fall apart and drop all the way down to a 3 seed.
Here's why...
If Dallas wins next week over Philly they would win the NFC East and take either the 3 or 4 seed. An Arizona win would give AZ the 3 and knock GB down to 6 with Dallas as the 4 and Philly the 5. An Arizona loss would give Dallas the 3 seed and Arizona would get the 4 seed. Green Bay's win over the Cards would put them at 5 and knock Philly all the way down to 6 with the Packers taking the tiebreaker over Philly due to better record vs common opponents.
If Philly wins next week over Dallas the Eagles would win the NFC East and would secure the 3 seed. Arizona would be locked into the 4 seed. And Dallas' loss to Philly would ensure Green Bay as the 5 seed.
So in essence these matchups would be locked in due to the 3rd tiebreaker in each case which is record versus common opponents. Arizona has it over Dallas and Green Bay has it over Philly. Of course this all all moot if the Vikings fail to secure at least the 2 seed.