Cool thanks for the details. I am going to give that friction lever on the handlebar stem a try for the drum brake. Seems like that is one of the better ways to do it and it surely was how the bikes came from the factory? The cable routing is designed for something at the front for sure. On the stem I meant the stoker seat stem, did you mean that too? It looks like is a suspension type.
You mean the stoker seat post? That’s a Tamer, which came with the bike. Seems to work pretty well, according to the stoker.