Curiosity of a Dwarf
2) The golems, both types, can be found in the Wastelands. You get the whole heartstones at about a rate of 1 in 6.
3) Rolento gives you an adena reward based on how many you bring back. For a Broken Stoneheart you get 50a, for a perfect Golem's Stoneheart 1000a, and if you bring in 10 or more items you get a bonus of 1183a.