Great, Amos. I read your post a couple of times, and got the bums and the tiddles sorted out. It does make sense. I've taught guitar in the days when you could turn on the radio and hear folk music--so people came for lessons knowing the sort of noises they wanted to make. Lots wanted to fingerpick.
My system was "RUN TO the CAN-dy STORE (1-2&-3&-4)" followed by the slightly more complex, "RUN TO the SU-per MAR-ket (1-1&-3&-4&). The first one translates into this, finger-wise: (Pinch[index/thumbtogether]-thumb-middle-thumb-index-thumb) After people got the pattern going by doing it over and over until they could disengage the brain...then the index and middle finger could get more selective letting the tune come out on the high strings, while the thumb filled in on the bottom ones. Sounds horribly complex, reading all that back to myself, but it worked nicely, and even the manually challenged could eventually manage to at least fingerpick an accompaniment. (Though it takes a bit of time to get where you can sing a song at the same time you're thinking about running to wherever.) Joan