This was part of the "dire" animal group that came in the Bones 4 Kickstarter. The material is Reaper Bones resin.
None. Mould lines were easy to remove.
Primed with Badger Stynlrez primer, brushed on. Miniature painted purley in oils. Mostly Winsor & Newton Winton line. Took not much more than an hour. Very quick and simple. Sealed with some matt varnish from Reaper Miniatures.
Custom made with shale. Very difficult to drill into, but not impossible. And honestly probably even easier than metal minis or some of the harder plastics like Mantic Games or Warmachine lines. The tree stumps were sculped from Sculpy clay. Flocking from World War Scenics.