I did have the concern expressed above that the reversed Pilcrow
in a box e.g. in an editor menu looks like it should create a new
paragraph,

I wouldn't be too concerned about that. The Pilcrow is familiar as an end-of-paragraph symbol, but I have never seen an editor that uses it to stand for "create paragraph".

Apparently there is a Pilcrow button in MS Word, but that stands for "show hidden formatting".

For my own package, I think that the documentation

https://github.com/allefeld/atom-pandoc-pdf#toolbar-buttons

should make it completely clear.

And once the symbol is used on the Pandoc website, users will automatically start associating it with Pandoc.

and isn't obviously recognizable as a logo.

A properly designed logo would certainly be nice. A while ago there was a comment from a designer on the repo offering to design a logo. I left a comment, maybe he chimes in.

But I would propose that for the moment we just settle on a font, and leave possible further logo design for the future.

And that would mean that you, John, have to decide which font it is supposed to be. :)