I believe I have a much simpler question that will shed some light on the TR-BoM[Feast] issue:
Why do you gain a card when you play Feast?
There are two possible answers:
(1) I trash the feast, then I read the second instruction on the card, and gain a $5. In other words, the feast can still dictate my activity from the trash.
(2) I read all the instructions on the Feast, and then I perform them one by one (as much as possible), regardless of the fate of the card itself.
The answer to this question is crucial, and all current rulings lead toward choosing (2) as the proper interpretation.
If I accept (1) as my answer, then a BoM can never truly be a feast in the first place. Once I follow the first instruction on the BoM, it is in the trash, where it is no longer a Feast, so I don't gain a card.
Donald's "burn-feast" example strongly implies that he intends (2) to be the correct answer. This means that the instructions on the feast must be "loaded up" into the gamespace and executed to the extent possible, no matter the fate of the card. In this case, the TR works the same way: pick a card, "load up" its instructions, execute them twice to the extent possible. This is why TR-Feast gets you two cards, even though the feast is gone after the first play. This would also explain why the TR-BoM[Feast] works exactly the same as TR-Feast: once the TR is played and the other action is chosen, the fate of that other action card is irrelevant to the execution of the game activities.
Think of it this way: when playing just a feast, the fact that it ends up in the trash after the first step is irrelevant, because it already gave you its instructions. When playing a TR-BoM[Feast], you read the feast instructions and execute them twice to the extent possible. The changing identity of the BoM once it hits the trash has no effect on this execution.
To everybody who mentions their confusion about the TR having "memory": it has nothing to do with TR. The game itself has memory, and it always has. The game has to have this memory in order to execute a simple Feast on its own. The TR just manipulates the game memory -- it doesn't create its own.