what did strahovsky supposedly do that was terrible? during the last conversation she revealed the part about killing her husband in the elevator scene but that was only to keep him from killing her first.
That wasn't in a conversation that was from the videofootage he found in the elevator (no it doesn't make any sense considering the angles are from everywhere and it's edited perfectly but that's what it was meant to be).
Anyway she didn't kill him as self-defence he was never going to kill her, sure he was a psychopath who deserved his ending but it wasn't self-defence. She was out of harms way when she decided to kill him, that's not to say that what she did was terrible but that's up to each person to decide I suppose.
what was the significance of her wanting a horse and her stepfather killing a horse in front of her?
He was just being a dick, he knew that she always dreamed of having a horse so he wanted to see that dream die in front of his own eyes, literally.
in what way did strahovsky "use / manipulate" brodY?
She claimed she was trying to figure out who killed her husband and needed his help and was willing to seduce him to get it, when it was her all along and what she really wanted was for him to go through all the video-footage and find the one where she gets busy with the old billionaire.
what did brody ultimately find out through his investigations that strahovsky did not want him to know?
She wasn't aware that the elevator had a camera with a microcard in it filming the murder of her husband, she never intended him to find out she did that. A good father and a good outlaw can't settle inside the same man.