I think more time would go into thinking "how would I do this again?" then the actual restore.
I would consider this very doable. I don't expect any data conflicts, since id's are not reused. All in all doable, but also time consuming because you want to do this really really carefull.
Every post ties to a user id, a forum id, and a topic id. The complexity of it is far beyond my capabilities. I'd rather chalk it up to lessons learned and tell people to think twice before deleting an entire thread.
