Maybe this can help… I copied the symbols from Smulf and added them to a dorico project. I used the same name as in smufl preceeded by accordion, for eg. Accordion Right hand, 3 ranks, 4’ stop (piccolo)
Accordion.dorico (565.5 KB)
I have included also the empty symbols, this allows for example to include in educational resources and draw the dots by hand.
I’m not and accordionist, so please check if everything is as expected.