I like everything you mentioned.  I would also suggest trying to
specifically appeal to both ends of the wide spectrum of museums,
ranging from the most professionally run to the most amateurish (which
is where I come in.)  (I realize it won't be easy to avoid scaring off
one group without boring the other.)

I do believe that some volunteers only casually committed can be induced
to make use of such a resource or at least read print-outs passed along
to them.  I know people who claim to want to learn but are unwilling to
even read the library books I recommend to them. One took himself off a
mailing list because it was "too much to wade through."  Maybe they will
respond more warmly to bits of info on a web-page???  It would be nice.
[I hope I don't sound too negative or shock the professionals.]