I thought everything worked... Then I discovered that when I turned the 3-way switches OFF from the 2nd level, the downstairs switch would not turn them back on.
Also found out that one of the terminals controls a bathroom light in my basement under the porch. After some study of online diagrams and my own, I think I've got it figured out. I think. I need to figure out which lines are Power and which lines go out to the lights...
So here's my plan - does it seem to make sense to anyone else?
I want to wire it so that my basement light always has power (there is a switch in the room itself), and I want to be able to have a switch on an outlet in the room (labeled R for Recepticle)