This has nothing to do with the rest of the story, but at the start of the final scene he tells the orchestra to take a break and says "We'll continue when you feel like rehearsing."
Obviously that isn't anything much, and it's probably about the SMALLEST angry thing he ever says to them, but it sounds sort of "snippy."

Yeah and it's probably something so subtle that the laypeople wouldn't understand. After all Alex is a genius according to Jennifer Wells.

Just another thing that bothered me but it involves Lt. Columbo. I did not like when he got into Alex Benedict's car at the repair shop. He hardly knows the fellow.

Columbo got out of character somewhat when he got a little risque with Audrey. That topic has come up before on this forum.

People always seem to forget ONE of his lines to Audrey. When she says "My mind or my body?" and he says "Both," he also says very quickly "Give me a break." And he says it in that panicky way, as if he's terrified someone will overhear that part. So he KNOWS that saying "Both" was kind of a dumb thing to do. And he's also ticked off that she even asks him a question like that, since it could really make trouble for him. So it's not like that part is pictured as completely all right by the story, either what she says or what he says.