I wonder of someone could check if my conclusions are correct in these sections from my rules document? It's easy to miss stuff with all this complicated stuff.
ENTRY: BORDER GUARD
* 2019-errata Lantern: The new version of Lantern triggers when you play any Border Guard instead of changing just your Border Guards. The differences are detailed below.
* Clarification: With the 2019-errata version of Inheritance, if you have your Estate token on a Border Guard and play an Inherited Estate...
(pre-2019 errata Lantern) ...the set-aside Border Guard is yours, so it will be changed by Lantern.
(2019 errata Lantern) ...you play the set-aside Border Guard, so Lantern will trigger.
* Clarification: If you somehow play a Border Guard that is in the trash or in the Supply (see PLAY A CARD WHILE LEAVING IT)...
(pre-2019 errata Lantern) ...it will not be changed by Lantern, since only your Border Guards are changed by Lantern.
(2019 errata Lantern) ...Lantern will trigger.
ENTRY: YOUR ESTATE TOKEN -- PRE-2019-ERRATA VERSION
* With Border Guard and Lantern (pre-2019-errata version): If you have Lantern, your Border Guards’ play ability is changed. This means that Inherited Estates will be changed: If you have your Estate token on a Border Guard, that card will be changed by Lantern, and your Estates will have the ability of that card. (On the other hand, Horn only triggers when you discard a Border Guard, not an Estate.)
* With Border Guard and Lantern (2019-errata version): If you have your Estate token on a Border Guard, Lantern will not matter when you play an Inherited Estate, since Lantern only triggers when you play a Border Guard, not an Estate.