XY-Problem: you are searching for ways to ignore guidelines about POB closure
a question that needs a longer/more detailed list of unique ideas/answers
That's basically the definition of "primarily opinion-based". Yes, a question can have an infinite number of valid answers. But: there have to be criteria for what constitutes a good answer and what constitutes a better answer.
If you are looking for long lists where everyone can say one thing that is exactly equally valid you are in the territory of "primarily opinion-based". And trying to force people into writing their point in a single community wiki to make that one the "best" answer because it's the longest one is the wrong way to solve this problem.
Your problem should be solved by stating what is important in an answer.
Use cases for community wikis
Community wikis are rarely used because there are only a few usecases where they might be useful. For example the graduated posts community wiki in the Sandbox allows people with 100 rep instead of 2k rep to edit the post, which makes it a lot easier for higher rep users as the lower rep users that use the Sandbox can add their links on their own. But that's here on Meta. On Main there isn't really any use for this sort of thing. You can simply suggest an edit if you are under 2k rep. But editing is supposed to be about clarifying a post, not adding your own ideas.
There are a few community wikis on Main. For example here is a usecase described by one of our mods. Basically on Main we could create community wikis when there are certain ideas coming up very, very often with very, very slight differences. That way you can point to the community wiki and say "Look there, that's one massive post that explains common timetravel/FTL communication/... problems" and update that whenever someone asks a good new question about the topic that includes things that weren't in the community wiki before.
Another usecase might be if you have a question and you decide to use a combination of the answers you are given. For example because one of them mentioned a few tangential points that made you change your mind. To inform future readers about what you in the end decided to do you could leave a community wiki answer that shows how you combined and changed the points mentioned and give credit to the corresponding answers. This is mostly to help future readers by mentioning the solution that helped you in the end and to not take credit for what is not really our own work. You used other peoples answers after all, even if slightly changed.
Tim B mentioned that he sometimes uses answers that were left in comments and turns them into community wiki answers. This way they are in the right place, as comments are not the place for answers and can be deleted at any point for any reason, but he doesn't take the credit from the user who really came up with the idea. This allows the previous comment-answer to go through the normal voting process and be visible to future readers.
You should notify the user in a comment that you are going to do that though, or you should be reasonably sure that they won't come back. For example I've seen people write something like "Don't have time, but if someone wants to expand on this you could start with...", which is a pretty good indicator that they are fine with you turning their idea into a full-fledged answer. Just be sure that it really is a full-fledged answer. You should also note that this is a specialty of WorldBuilding.SE, as answers in comments are generally discouraged and on many StackExchange sites immediately deleted upon sight, for example on RPG.SE, which is a community with very strict rules about comment usage. We are very, very lenient in that regard.
Don't try to force people to use community wikis
But you shouldn't force people to write a community wiki for your single question. In such a case like the above it might be useful to first start a meta discussion about whether we really need something like that and to raise awareness that you are trying to make a canonical question and answer for a certain often-asked topic.
Other sites don't even use community wikis for canonical questions. Look at Why is Kali Linux so hard to set up? Why won't people help me? The highest rated answer is a community wiki because the idea was to have one canonical question to point to whenever a newbie asks about Kali Linux, but there are still other normal answers and the question is a normal question, too.
Even on Puzzling.SE, where people often write partial answers you rarely see community wikis.
SFF.SE uses community wikis for certain identification questions with long lists of things, but not even there the usage is consistent. There may be some people wondering why you don't edit the community wiki, but nobody forces anyone to use the community wiki.
Community wikis are not what they were initially used for anymore
The usage of community wikis has changed over time on the network. For example in times past answers and questions were automatically converted to community wikis when there were 30 answers or more and it was a tool to make people answering opinion-based questions stop farming rep. It was basically a punishment for the people answering questions that are not a good fit for the site. There were other mechanisms, too, that were abolished in 2014.
The main reason was that it's easier to edit, but with the "suggest edit" feature this main advantage was basically nullified on Main sites. To cite:
With suggested edits now in place, you could argue that the removal of reputation from voting is now the only function of community wiki. Unfortunately, this means it is often seen as a magic switch to allow questionable content.
Community wikis are not a tool that suddenly allows any kind of question just because people could more easily make one really, really big answer.
If a question is valuable enough that you believe it belongs on the site, chances are you don’t need it to be community wiki!
Community wiki is like a cheese knife: it is a specialized tool to be used sparingly.
If you really want to make people interact with your reasonable community wiki answer ask on Meta
For those reading this and wanting an answer to the question about getting people to interact with community wikis: you can't. There is little incentive apart from making a canonical question, so your best bet is to make a meta discussion and ask folks to help you with a canonical question/answer for a certain kind of topic that comes up pretty often. Other than that you just have to accept that people are free to interact with community wikis or not. Bounties are not awarded to people participating in community wikis, votes don't count once it has been turned into a community wiki, your username only appears if you are the person with the highest amount of content contributed to the community wiki, ...
It's a nice tool, but apart from asking people nicely to add something you don't have any tools available to make people attract users to community wikis.
The goal is not to help the asker of the question. The goal is to help all those people that will have a similar question in the future and stumble across the post. You need people that like that fuzzy feeling of helping people in the future and therefore contributing without any other acknowledgment.