Is the Teufelberger safety pro 12 a natural crotch rigging rope? And how does it compare to the Samson arbplex?

Yes you could use Teufelberger Safety pro 12 for natural crotch rigging. If you tend to run ropes frequently in tree removal rigging situations I would recommend getting some rigging thimbles through. At that point no rope is natural crotch proof. 

I would say that Samson Arborplex is a little more flexible in the hand. Teufelberger Safety Pro 12 is a little more stiff feeling. Safety Pro 12 also seems to have slightly larger strands for what it is worth.