Giving knights the ability to flavor estates sounds fair, though keep in mind they are all reset when a region is lost, and that lords can and more or less regularly open and close them.
Newspapers were propaganda, that's what they were about. If someone just wanted to write to one's own realm mates, one already can pretty easily. The purpose was also to reach out to foreigners. Made them interesting to read, too, for the most part. They could be handled in game, though, in the information tab perhaps, and every entry could be pushed automatically to the wiki by the game itself. A notice could be sent out to the continent every time a new article appears, and everyone would have the option to mute notices from specific newspapers. Some restrictions should be had, though, to avoid people using it as a means to quickly relay information to the whole continent (15k CS of Bobistan in Smallville!) as a lazy means to target just a subgroup of it. Perhaps delays in publication. Not sure how much work such a thing would require though.
Periodic updates to everyone seems fine. Every 4 months, perhaps, everyone gets an update "the X bulletin was last updated Y months ago", with a link to it. Most bulletins take quite a while to "expire" though.
I think lords being able to open, close, delete, etc. estates is completely fair and realistic but if a region is lost then perhaps estates shouldn't just get wiped? They could become vacant instead (and if the region is rogue then obviously no one should be able to take up an estate) so it's then up to the new region owner to decide if they want to keep/modify the existing estates or not. I mean it's already the case that one region lord can just wipe the description given to it by their predecessor but I don't think fluff should be wiped unless a player action causes it to happen.
In terms of updates about the bulletins perhaps they could just be a six-monthly reminder of what the bulletin currently says. E.g. "Reminder: The Ruler Bulletin currently says X (and was last updated Y months ago)." That way you don't feel pressured to update it just for the sake of doing so but people will notice if it's become outdated.
In terms of newspapers I think that preventing sharing of detailed information could just be a matter of a strongly worded warning at the top of the newspaper article writing window. But equally, if someone wants to write a newspaper article saying "Our glorious army marched from the capital of Kepler today to attack the vile enemy stronghold of Butterville" or post a summary of a battle that's happened then I don't think that should be a problem - besides, if you're foolish enough to rely on your enemy's propaganda to keep track of what they're doing then you're just asking to be fed deliberate misinformation
