Like a lot of people here, without hating it, I've always had trouble getting into the later COLUMBO. But I do like "Jackpot," so Freddy Brower is about the first victim in the later series I think of. Gary Kroeger is a very underrated actor as far as I know.
As I've said before, no one could play a "hard luck" character better than Don Gordon, so I've always liked Alvin Deschler too (I just left him out accidentally). And for an ex-convict, that gratitude of his makes him so naive when it comes to Galesko (just as Steve says), so that's another way he's likable.
True, Alvin was scamming Paul a little. And there usually is a high rate of ex-convicts returning to prison. Alvin probably wasn’t truly reformed if he was involved in a scam so soon after his release. And that he was a convict in the first place doesn’t make him totally innocent.
What about Paul Williams (Ransom for a Dead Man) as a likable victim? He isn’t on-screen long, but the way other characters describe him, he sounds like a nice, decent guy.
I know what you mean about Alvin, but Don Gordon always makes me like him. And again, even if he is scamming Paul Galesko a little himself, he's such a "babe in the woods" when it comes to Paul that you feel bad for him for that reason.
Sometimes I wonder if that detail about Alvin scamming Galesko was put in to be a clue to Columbo that Galesko just picked an easy sap for his own purposes instead of somebody who was truly reformed/reformable...along the lines of Dale Kingston in “Suitable for Framing” attending and reviewing the art show featuring Sam Franklin’s inferior work. That provided Dale an alibi, but under normal circumstances, Dale never would have wasted his time there. Maybe it’s similar with Galesko? If Galesko were sincerely interested in helping a convict turn his life around, he never would have picked Alvin?