I didn't think that you did. You can't derail it by yourself, anyway. This topic is very interesting, and I appreciate your input, and also the thread being started...
My opinion:
If I were Terri, I'd have hired a defense attorney the moment that I felt I was being targeted in the investigation. I would have ceased talking to investigators as soon as it felt like the questions were indicative of me being suspected as playing a role in the child's disappearance.
However, Terri didn't hire an attorney until much later. Why not? In my opinion, it's because she thinks of herself as an intelligent creature who's far smarter than her husband, the investigators, the DA, and the public. She thought that she had planned the crime so perfectly that her answers would allay any suspicions of her participation in Kyron's disappearance. Only when her answers to investigators' questions did not suffice, only when her domestic strife snowballed out of her control and her husband moved out, only when she became the primary interest of LE did she hire Houze.
Me? If I were Terri, I'd have sought a defense attorney when the questionnaire with specific questions about me was mailed out, if not before. But Terri thought that she could use her "charm" to answer any questions, and that LE would be content with her explanation. To Terri, her public persona is everything, and hiring a criminal defense attorney earlier than she did would have, in her eyes, been tantamount to an admission of guilt...it would mean that her facade was crumbling. She knew that the moment she hired a defense attorney, it would mean the end of her marriage, the end of her hopes to teach in a classroom, the end of her supermom reputation. I think she thought that if she just kept BSing, the problem would go away. It didn't.
Here's something else to consider. Houze's strength isn't only in his ability to present a defense in the courtroom. He's also a master negotiator. If and when Terri faces charges, we'll see the negotiator go to work. There may never be a trial.
As usual, all my opinion, based on my interpretation of everything that I've read.