Except the FAQ doesn't say the source is the ship choosing, the FAQ says the source is the ship equipped with the upgrade/ability. From the FAQ:
"When using M9-G8, the source of the reroll is the ship equipped with M9-G8, not the ship attacking. For example, if a ship is attacking with Snap Shot, a ship equipped with M9-G8, can cause that ship to reroll a die."
Again, it does not say that the source of the reroll is the ship choosing the die, it says that the source is the one equipped with M9G8.
Look, it would be much simpler if FFG had simply ruled in a manner consistent with the wording on the cards. M9G8 would not work, R7 would work, Palpatine would be unaffected, "It may reroll" or "the attacker may reroll" would mean that the ship instructed to do the reroll is indeed the source of said reroll. That would make an ENORMOUS amount of sense to me, and be much easier to understand/explain. But they didn't. FFG said the source of a reroll is the ship equipped with the ability, so that's what we really should be going with for the time being.
Who knows, maybe they will change their mind and rule that these cards really mean what they say, and save us all a lot of grief. Eventually.