The defense in court cases is customarily on the left side of the court, the judge's right. With the prosecution on the right, the judge's left. For some reason, they have reversed that in this story-line.
In the long shots of the lion enclosure (when the lion is present), Dr. Braun's feet are splayed out unnaturally, his right arm is curved unnaturally, and his face is pointed down, all indicating that a dummy was used in the long shots. In the last close-up shot of the body, the lion is no longer present, so a real person (presumably Dr. Braun - or rather Leslie Bradley) could be used.
The defense is seated on the opposite side from the jury, not on the left or the right side of the courtroom. If the jury is to the right, the defense is to the left.
When Perry goes to the zoo to speak to Boris the lionkeeper, he finds Boris with Frieda Cranston and gets introduced to her. But Perry had already just met Frieda when he visited Braun's dentist's office. When Boris and Frieda refuse to answer his questions, Perry threatens that the next time they meet, Boris and Frieda may be on a witness stand in court. This conversation and warning take place before Tony Osborn, Perry's client, is a suspect and is charged with murder.
When Perry informed Boris and Frieda that the next time he questions them may be in court, before anyone was arrested for murder, Perry may have been referring to a motion to protect property to wit: the pending destruction of the lion. Perry stated to Boris his answers may prevent the lion from being put to death.