Interesting, can you find that scenario? Other places are reporting the Eagles can't get the 1 seed but definitely possible there is some obscure scenario that not many people are picking up on it.
Edit: In fact, the only way all 5 teams tie at 12-5 is with the Bears beating the 49ers and then SF beats Seattle (because Seattle has to lose twice to finish 12-5). If that were to happen, the 49ers would win the division with a 3-1 H2H record vs Seattle/LAR, compared to 2-2 for Seattle/LAR. If I'm reading the tiebreaking rules properly, if one team has a H2H sweep, they would win the tiebreaker, and in this case the Bears would be 2-0 against the 49ers and Eagles, the 2 teams they would be tied with.