At least two scenes take place in a Baptist church. Behind the pulpit is a Roman Catholic cross with a Corpus (body of Jesus). Baptists, like all other Protestants, never place a Corpus on the cross.
When Celie and Shug go to see "The Flying Ace," there is a full score on the soundtrack. "The Flying Ace" is a silent film, and there are no musicians in the orchestra pit, not even a piano.
Towards the end of the movie, when Mister gives the box of memorabilia to Celie, one of the things in the box is Nettie's straw hat. But earlier in the movie Nettie is seeing wearing the straw hat while she is in Africa.
With the Gramaphone, the Reproducer, that holds the needle, is on the wrong side of the record and in reality would not work.
In a scene set in 1917, one character says "This is better than a radio show." But radio was still in an experimental stage at the time. The first radio station in America, Pittsburgh's KDKA, did not start broadcasting until 1920.