I may not agree with your deductions, @MassGuy, but I think your deductions are logical and coherent. I like the framework you just mentioned.
Five of the 6 factors you describe logically militate toward a belief that Barry Morphew may be involved in Suzanne's disappearance. The only factor I disagree with you about is the sixth one: the subject's behavior.
First, I simply don't think there is a "model behavior" that every person with a missing spouse will exhibit because humans are each so different. Just as each of us is influenced by genetics & environment, so is every other person. As much as we might presume that a person may react a "certain way" when a tragedy occurs, that doesn't mean our presumption is correct.
Second, I believe that humans may change their behavior based on external factors. Today, it is axiomatic that a missing person's spouse is the first person suspected. With that knowledge in mind, why would it be surprising that some spouses choose to exercise their rights to remain silent? They may fear that investigators want to ensure a swift end to a mystery & have tunnel vision. Is it unusual behavior? Yes. Is it unreasonable behavior? Absolutely not.
I agree that -- applying 5 of your 6 factors -- Barry may be involved in Suzanne's disappearance. However, I have yet to even see the search warrant probable cause affidavits, much less actual evidence linking Barry to her disappearance.
BBM — The Behavior of those close to a victim of a crime, and what they say as well as what is not said, is all part of profiling. Law enforcement professionals understand and appreciate the importance of behavioral anomalies. These verbal and nonverbal signs of cognitions and emotions provide additional clues to what an individual is thinking and feeling beyond the content of the words being spoken. In the context of an investigation, these behavioral anomalies are called indicators.
More on the FBI profiler:
https://www.math.uci.edu/mathceo/Files/Career_presentations/FBI.pdf
Behavioral Science Unit - Wikipedia