Great questions!
For the first question regarding the decision and proposal tag, they may actually be redundant. All proposals will need some type of decision, so the presence of a proposal tag should also indicate that a decision is happening there. I suppose my original thinking was that something like Notable Works or Key Questions would also come with decision tags, providing that tag with utility across the forum. Threads like the SCRF Terms Glossary and Content Tags might also benefit from a decision tag so that people could filter by the decisions that the SCRF community has made over time. Perhaps to start with, just the proposal would make sense.
Regarding the second question about research-oriented community events, I think the key here is to make sure we are highlighting research content above all else. I am interested in seeing the success of this community category, but it is a support category to help us produce more research content. If we have a live chat about a research summary, I think that the output on the forum would be best categorized as a content type in the appropriate research category. For example, a live chat on cryptography would go in the Cryptography category. Even a reading group that focuses on a core cryptography paper should probably have output in the Cryptography category. Perhaps the planning of these events could be facilitated by the Community category discussion, but the output itself should be in the research categories if possible.
Thanks for the opportunity to do some thinking through those.