In the scene where the women go off to search for Dr Mike and Sully, the shot from behind shows Mrs. Quinn, Anthony and Horace waving goodbye to them. Mrs. Quinn is on the left. The next shot show the faces of the three with Mrs Quinn now to Anthony's right.
When Katie is first born, it is a newborn. When mike and sully arrive back in town and townsfolk are seeing the infant, it's an older baby. The baby is very alert and smiling at the attention. Newborns are not that alert and only very rarely able to smile.
Dr Cook told Horace an active lifestyle helps food move through the gallbladder. But in reality the gallbladder stores bile and releases it into the stomach after meals. No food goes in there at all.
Sully's broken leg would have swollen so much that his boot would have had to be cut off.
Horace is seen wearing a wedding ring, but men did not start wearing wedding rings until World War I.