How to attach the balusters to the treads, that was the question. As I recall, some have drilled holes and inserted wires or wooden pegs. I didn't have either on hand, so E-6000 glue to the fore. It will hold just about anything to anything and is strong.
A coat of clear satin acrylic will be applied to all of the staircase sections when they are all finished. The next step is to tackle the ground floor stairs, which have two landings and need to be jury-rigged so as to slide in and out smoothly. I've ordered some flooring material, which means a bit will have to be shaved off so they'll fit.