I've definitely followed the podcast, but it's been a long time since I listened to season 1 so I don't remember Josh ever saying he didn't think Kami and Gene were victims. My read on it is he seems like he thinks it's a strong possibility now--I'd guess he feels more strongly about it than I do--but who can really say?If you've followed the podcast you'll know that Josh looked into their case in depth early on and concluded that they weren't Keyes' victims. Recently, however, he has revisited the case and is not so convinced that they can be ruled out.
I don't recognise these people but maybe they were discussed in an early season and I've just forgotten them.
And Petrone and Imbo were on the Namus 45. They are the only couple on there aside from the Curriers. As far as I can recall they have only been discussed in passing on the podcast because there's really nothing to suggest that Keyes either was or was not responsible for them. I'm pretty sure there's a Namus 45 episode on them though.