Looks like 15-2 by the Lions wins the #1 seed no matter what.
- If lose to Buffalo, then beat SF Chi Minnesota, will win the division because the Vikings would top out at 14-3. Would finish ahead of Philly with a 11-1 conference record because Philly would top out at 15-2 with a 10-2 conference record.
- If beat Buffalo, lose to Chicago, but beat SF and Minnesota, will win the division because the Vikings would top out at 14-3. Would finish ahead of Philly even if the Eagles win out because the conference record would be tied at 10-2 each but the Lions would win the common opponent record 5-1 to 4-2.
- If beat Buffalo and Chicago, lose to SF, but beat Minnesota, will win the division because the Vikings would top out at 14-3. Would finish ahead of Philly even if the Eagles win out because because the conference record would be tied at 10-2 each but the Lions would win the common opponent record 5-1 to 4-2.
- If beat Buffalo, Chicago and SF but lose to Minnesota, the Vikings could top out at 15-2 to match the Lions. Lions-Vikings head to head tied at 1-1. Division record tied at 5-1. Lions would win common opponents 12-0 to 11-1, since the Vikings lost to the Rams. So the Lions would win the division. Would finish ahead of Philly even if the Eagles win out because because the conference record would be tied at 10-2 each but the Lions would win the common opponent record 5-1 to 4-2.
Correct me if I'm wrong! (but I don't think I am).
FWIW, tiebreaker order is:
https://www.nfl.com/standings/tie-breaking-procedures
For Division
1. Head to head 2. Division record 3. vs Common opponents 4. Conference record 5. Strength of victory 6. Strength of schedule
For Record
1. Head to head 2. Conference record 3. vs Common opponents 4. Strength of victory 5. Strength of schedule