I think TR selected an action card from your hand, which was most definitely BoM at that step, since it hasn't been (about to be) played yet. At any rate, regardless of whether it selected BoM-as-Feast, that card is no longer BoM-as-Feast by the time TR2 rolls around.
(Obviously, Donald has prerogative to issue clarifications or errata whenever he feels, but I don't think the cards as written suggest the ruling as given for TR-BoM-Feast.)
Yes, but you're Throne Rooming a BoM-as-Feast, not a BoM simply. To "Throne Room" something is not simply to choose it with Throne Room, but to also play it with Throne Room. To be "activated" by Throne Room means both chosen AND put in play, and as soon as you say "play," BoM is a Feast (or whatever). You don't stop saying "play" until the Throne Room has run it's course.
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Essentially:
Play Throne Room.
Choose a card. (What card? BoM.)
Play that card twice. (What card? BoM-as-Feast.)
vs.
Play Throne Room.
Choose a card. (What card? BoM.)
Play that card twice. (What card? BoM-as-Feast.)
Play the chosen card. (BoM-as-Feast)
Reevaluate the status of the chosen card.
Play the chosen card. (BoM)
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Scenario 1 looks like Throne Room... simple and direct.
Scenario 2 adds in a lot more that isn't simply or directly on Throne Room.