Good questions, but I would add one more possibility that raises more questions.
Assume the FBI statement is true that the bombs were actually dangerous. Is it possible they intended the live bomb at the DNC, which appears to have been planted at the last minute, to blow up VP-elect Harris?
Her statements now might not make sense because they never told her the truth.
But think of the tremendous sympathy for the incoming Biden administration if his VP was killed or seriously injured by the “MAGA bomb planted by enemies of democracy.” Think of the tremendous power to wipe out “right wingers” this would have given them. Trump would be at Supermax now, if not already hanged.
Harris may be extremely indebted to Ray Epps for making the Capitol incursion a success.
That certainly is a thought-provoking consideration.... and given how evil the DS has proved to be, not something that should be dismissed.