To deal with moderation conflicts you could basically just unlink the thread.
Also we could also just add flags to activitypub messages on creating posts to tell the boosting server whether or not merging is permitted.
If you’ve worked hard on something and want everyone to see it, set it to True and people can boost it to different communities.
If it’s something personal or an in-joke that you only want to be advertised to the community it’s posted in set it to False and the option won’t be available when cross posting in the UI.
I’m all for scamming scammers, but I’m quite happy to give a tip to YouTubers I watch by way of e-commerce commissions.