Some of these seem overly strict, and people might miss notifications they'd want.
E.g. topic renames are pretty rare, so it seems worth notifying everyone who is watching the topic (currently it is just original topic creator, and the talk page owner if it's user talk). There are probably other cases.
See user-locators fields under https://git.wikimedia.org/blob/mediawiki%2Fextensions%2FFlow.git/master/includes%2FNotifications%2FNotifications.php#L11 . That references EchoUserLocator and Flow\NotificationsUserLocator.