The rear brake is a stirrup type rod brake. I think I can get it to match by making part of the rod a little longer, but if I can't it's easy to remove and there's a coaster on the hub (and the rear brake has never been great anyways: steel rims, long mechanical linkage with a good amount of flex, no mechanical advantage, ...).

The current tires are 2 by 1 1/2. Getting a wider tire for the rear wheel to bring it up to closer to the same size would make sense.