"I'm looking at ways to make Yoshimi as inviting and easy to use as possible for
complete beginners and one of the stumbling blocks seems to be initially
getting any sound."
AS YOU CAN CLEARLY SEE, I tried to help. I provided a simple clear, explicated
question and scenario and was met with pure derision by the majority including
some listed on your webpage as significant. And worse it turned out as an
insult-fest perpetuated by 2 more members -> see 12-2018 archives.
Little help, by way of one individual was supplied. Was attacked by 3 people.
Regardless, I provided and contributed a step-by-step solution including some
dev notes you may want to consider as a priority improvement towards GUI
(Graphical User Interface, excuse my miswording or any confusion, must have
been a Freudian slip).
Also my Freudian slip points to another issue - and this relates to your
mailing list members or at least some more vocal members who made matters very
hard (as possible) and demoralizing towards "beginners" seeking to use a simple
synth and mid controller.
I'll refer to this as your mailing group's General User Interface. That is is
definitely broken.
Good luck.