I never found an authored report for either of these formerly missing people. I did find a legal notice for James P. Freund, however.
Clipping from Intelligencer Journal - Newspapers.com
Yes, it appears his wife went through the process of having him declared deceased. It took a couple years, apparently, you'll see legal notices published between 1986 and 1988. IANAL, but it was probably the process for Pennsylvania and varies from state to state and over time. It's possible she suspected he was deceased and took this step to help qualify their daughter to receive survivor benefits from Social Security, etc.
At some point, Jim's family probably assumed he was deceased. It doesn't appear his life was "out of control", IMO. He was doing what a lot of people did back in the early 70's. He had married and started a family while still in his teens, served in the military and ended up in an unhappy marriage. He lived in a small town/city where he probably felt his life was boring and predictable. Living the single life there after divorce was probably no picnic, with his ex in the same city, lots of gossip and the only women to date being people he grew up with and knew his ex wife.
He probably saved up his money and took off for Colorado, just to get out and live somewhere new, meet new people. Maybe he even considered going to college to get a degree. With his training in mechanics, he may have had good skills and found good paying work as a mechanic. Traveling to see the country was something a lot of guys did who were his age, not long out of the military.
In the early 70's a lot of young people, free spirits were moving to Colorado. John Denver and other musicians made it a popular destination, especially for those who loved the outdoors, skiing, etc. It attracted a lot of artists, musicians, writers, etc. Pam may have ended up there for that reason. She probably settled in around friends, married, got a divorce, etc. Somewhere along the line she probably met Jim. Maybe she was still singing in coffee houses or open mic nights at clubs, etc. They hooked up, maybe decided to take a road trip, go to Florida to see the stock car races at Talladega and ended up running into a very dangerous criminal who killed them.
All JMO from what is known so far.
ETA: When I was in college during the mid 70's, there were quite a few military vets who were also students. They were in Jim's age cohort, background, some divorced, a few years older than the rest of us. Most lived off campus, in their own house. They received GI benefits. Nice guys, kind of like "older brothers". Had pretty wild keggers.