I'm afraid I don't see how they can be on topic
I assume this will not be a popular answer considering the positive votes gained by the posts listed in the question. I realise that there is a desire to mourn the deaths of beloved members of the SFF community, and I sympathise with it. However, there are many places to do that.
This site has rules that include adherence to a Q&A format. We downvote and close "questions" from new visitors that take the form of forum posts rather than true questions that can have concrete answers.
I don't see how we can justify closing those questions if we decide to make exceptions just because we would like to.
In response to comments
I realise that Meta is also used to make announcements about the website, such as moderator elections and changes to the Terms of Service, but those are announcements that must be made available to all participants. I don't think they are in the same category as blog or forum posts that happen to be of interest to a large number of people.
I don't dispute that the community can decide its own rules, or claim that it needs higher authority to do so. I suggest that selectively creating exceptions to the rules will weaken them and invite more off topic posts.
Again; I mean no disrespect to Carrie Fisher, and I include myself among those who mourn her. I just think there are more appropriate places to express these thoughts.