If I have to make 30 or 40 chairs, and I dont want to fully assemble them until I need them for an order, the dowel idea is great for me, I can set up a jig in the drill press, drill all holes at same time, extremely time saving, thats why I figured glue in a dowel at stress points, one for each leg, and just hold it in place with a few pins until glue dries, this way no screws, pins would not be used for strength, just to hold in place to allow all glue to set.
I can pin in a few back slats, glue should most certainly hold them in, they arent under any stress. I want to have the option of painting them all colors, and screw heads are very time consuming to cover up.
my cousin the artist feels she can sell kiddie chairs and tables and fat persons adirondack chairs,(hold up to 500 lbs, make them 24-26 inches wide also)
at the shows she attends, or would attend next year.
shed paint an animal or something on the chair back, first spray paint the chair a specific color if asked.
Me, Id just do like I do with the adiriondack chairs, make all the parts and store them in piles, wait till I need them.
Id use white oak for all of it.