It is interesting that the voice actor was available and willing and yet Telltale decided not to use him. I get that Bosco and Jimmy would not have worked as reoccurring characters because of the way the story was structured but it does seem like they could have given one or both characters cameos at some point.
I always just assumed the voice actor was unavailable for some reason and they had to write around it. If they do do a season 4 I think they'll have to bring Bosco back in some capacity.
"Now, if you'll excuse me, I have some massive internal hemorrhaging to attended to."