I realized that the guy who wanted the business information was always kind of transactional. He'd want to get together if I could help with something. Other times, we'd discuss getting together and he never would want to finalize plans. So, I gave up trying. That's why I hadn't had contact in a while. I guess it's not surprising he only got in touch now when he needed something.
The woman who wanted the classes for her kid did the falling off the map thing once she became a mother. We were in touch sporadically, again talked about doing things, but she canceled several times due to kid-related stuff, so I accepted that seeing me wasn't a priority.
The other woman I knew from an online forum. She's friends with a family in my country. We got together several times a while back when she was visiting, and had a nice time. However, since then, she messaged me 3-4 times about this family - supposedly they weren't answering the phone or texts, and she wanted me to try calling them from here. Then, she wanted me to try and track down one of them. Exactly how she expected me to do that, I don't know. She said internet searches didn't show anything. She described the area where the woman lived, which could be any of 100 neighborhoods in a city I no longer live in. Was I supposed to go around to these neighborhoods with a picture of her to see if I see someone that looks like the picture? It was bizarre. Maybe they got sick of her too and that's why they aren't responding! She also wanted me to see if there was an obituary. Anyways, the last time she did something like that, the tone of the message was pretty aggressive, almost demanding. Then only after that did she write, "I guess I should ask how you are." I looked over the text history and I just saw it was all about what I could do for her. I told her that I thought it was rude she only gets in touch to ask me to do something. She gave the non-apology, "I'm sorry you feel that way." That was it for me.
Fortunately, I have other friends who check in to ask about me, and vice versa.