Figured I would create a topic here to help people getting started or who might be starting their search soon.
1)They seem to be scattered randomly around islands/uncharted islands with a cap at 3 statues per island (from what I have seen thus far). They also have an audio cue to help locate them.
2)*Sapphire and Emerald statues are soloable, the Ruby statues are duoable they just take a bit longer.
3) Sword+Blunderbuss seems to have the best initial dmg output and there is a sweet spot you can find with your sword where the statue can't damage you, but you can damage it.
4)I have found statues at N10/K14/Cannon Cove/Lagoon of Whispers before I had to leave for work