mtg commander decks d&d Legend's Legacy Dominaria United Deck – Magic Precon – Ventura Games Swerve through three planes of mayhem Commander Deck -Set of 2

Yes, moving counters from one permanent to a second counts as putting counters on that second card , which matters for effects like Doubling Season or Emperor of Bones

The answer is yes

Spare parts are essential when it comes to system availability and readability

(If they're equipped to the same creature, the abilities of the equipped creature will also trigger three times.) An ability of the equipped creature that triggers when a card is put into a graveyard "from anywhere" triggers twice only if (a) a creature card was put into a graveyard from the battlefield and (b) The Masamune is still on the battlefield and attached to the creature with the relevant ability