> As in, suppress author on first item, but not second, as opposed to all items within the citation.
> In retrospect, does this make sense?
I’d say yes, there may be things such as
«In his mail to the mailing list, D’Arcus (2021; against Doe 2020) has had a couple of questions about citation syntax.»
Not quite pretty, but reasonable, isn’t it ?
Regarding the style vs minus question : in pandoc you can’t have a thing such as this syntax : [cite/text:@key1;@key2]. So using symbols is the only possibility. Org is different in this regard. Possibly you could use a special style for that. But the symbol based syntax can give you a nice shorthand.