Finally it was the week of the play.I would put a comma after finally. Also, the last two sentences are in present tense, but the rest of the paragraph is past tense. I think it would be better just to change the last two sentences to past tense.
The great oak doors closed with a soft, but firm thud behind the Welch's family as they entered the church. However the noise sounded like a thunderclap in the crackling tension that filled the room. Aware that they were being watched out of the corner of many eyes, the family quickly took a seat in the back pew. When they had all filed in, Mr. and Mrs. sat and paid respectful attention to the man speaking, the two younger boys figited in there rarely-used black dress clothes, and the older boy who at least attempted to look like he cared. But Adrian's face muscles were tight from trying to remain a neutral expression.