I made a test character in single player (1.40.4) to test Unarmed feats and Nature's Warrior. The test character is Human level 18 with BAB 16: 7 Druid, 5 Nature's Warrior, 6 Fighter. I chose Armor of Crocodile, Claws of the Grizzly, and Wild Growth from the Nature's Warrior list. The character has Weapon Focus, Weapon Specialization, and Weapon Master in Unarmed Strike. I tested the Treant, Shambling Mound, and Dire Bear, Dire Panther, Dire Wolf, Dire Boar, and Dire Badger.
The Good:
1. The Claws of the Grizzly add +3 magic damage to all attacks in all forms.
2. Weapon Mastery adds +2 Attack and +2 bludgeoning damage to all attacks in all forms.
The Bad:
1. On the character sheet where it lists the damage (f.x. dire badger) as 1-4+X, the X should be the combination of Strength modifier plus Weapon Specialization. None of the forms include the +2 damage for weapon specialization. They only include the Strength modifier.
2. Not all forms add Weapon Focus. The Attack number should be BAB + Str mod + WF + WM, but Shambling Mound, Dire Bear, and Dire Wolf are 1 Attack short of where they should be. I assume this is the Weapon Focus not being added correctly. The Treant, Dire Panther, Dire Boar, and Dire Badger display the correct Attack number.