Due to the topic of the community, there might be some heated debates and discussions in the comments (the example above with the vegan cat food is a good example). That might be quite time-consuming to follow and moderate
Based on this, I think we would need probably at least 5 mods to make sure the community stays sufficiently moderated.
Maybe, but if it's limited in scope to memes about the Fediverse, the community might not exactly be overrun. Hardly anyone in the Fediverse memes the Fediverse, and outside the Fediverse where the huge majority of memes on Lemmy come from, nobody does.
That is, if such a community exists, maybe it'll drive people to meme the Fediverse in the first place.