I think it can very well be applied to the Threadiverse.

• Sin #1: The First-Move Problem - Doesn’t really applies for the Threadiverse, because the instances (at least for me) do feel genuinely different, with a different culture, etc., which is one of the most exciting things for me here
• Sin #2: Navigation Inconsistency - Basically the same here.
• Sin #3: Remote Interaction Hell - Also the same here, right?
• Sin #4: Private Mentions Aren’t Really DM’s - Same here, right?
• Sin #5: The Phantom Social Graph - There definitely are synchronization issues on Lemmy, too (see the australian instance, which, I think has a latency of a week of so per post :D). Otherwise because the Threadiverse is still rather small, it seems to work mostly fine.
• Sin #6: The Discovery Problem - Much better on Lemmy. The algorithms are both transparent and make the threadiverse feel alive even though it has much less user.
• Sin #7: Basically doesn’t apply here, because you don’t follow users, but can be applied for communities. And multiple of the same communities on different instances are a big problem of the Threadiverse. Also abandoned communities. PyFed solves this with topics and Lemmy also has an upcoming feature for this in v1.0 I think.

I think the most pressing issue is sin#7 if applied to communities.