Character mistake: After Rosemary has the baby and they tell her it died, she calls them liars. They give her an injection and she passes out. When Guy comes back, he says that the Doctor says she was suffering from prepartum (not an actual word) symptoms. It would actually be postpartum.
Suggested correction: Actually, it depends on which time her 'crazies' were from. If Guy was referring to how she acted while still pregnant, then pre-partum would be correct. If referring to her tantrums after the birth, then it would be post-partum.
The post starts. " After Rosemary has the baby...".
Character mistake: In the beginning of the film, Oliver has been brought by Mr. and Mrs. Bumble to the Governor's door after asking for more to eat. Mrs. Bumble then sings, "They'll lay the blame on the one who named him," and as Mr. Bumble is responding, "O-li-ver", look at Oliver. He is completely spacing out and not in character at all - staring off into the distance and flicking his tongue in and out of his mouth.
Suggested correction: The character is in character, he is acting alarmed and concerned and regretting his choice to inform the governor. As seen https://youtu.be/nlJugdk4OGc.
Character mistake: A space traveler would not be "going to Orion." The major stars in Orion vary in distance from the earth from 243 to 1,360 light years. Orion is only a constellation as visible from Earth; once you get away that far, the stars would not be in the same alignment as they are from Earth. They would have been going to a specific star, probably Bellatrix at 243 light years, as Taylor mentions being at 320 light years.
Suggested correction: I'm not sure what scene you're referring to, but I never heard anyone say they went to Orion. Taylor says they're on a "planet in orbit around a star in the constellation of Orion. That could be Bellatrix." To Taylor, who is from Earth, the star is still in the constellation of Orion.
I agree with your take, but I still think it could be interpreted as Orion's stars all being in close proximity. And I would hope they would know about the 320 - 243 light year issue.