Tags and subforums sound like they would have significant overlap.
probably. the use case I have in mind for tags is that you can tag proposal threads as "pending", "approved", "enacted", "rejected" and so on, while still also having the option to see all proposals in one place if you want.
Also, perhaps a general reactions system is nicer than voting, unless you intend to use it for ranking.
perhaps. allowing voting options to be configured per-subforum could potentially be useful in certain cases. I am intending the voting system to be used more for literal actual voting on some thing contained within a post, rather than as a ranking system: I don't want to create a reddit clone here.
Also, search WHEN?
maybe