I will post a question in answers.unrealengine because this seems to be a bug because :
The same setup works very fine in third person template , it attaches staticmeshes , skeletal meshes , blueprints to the defined socket . but the in first person template it simply doesnt work . it gives an error for static mesh when exiting play session , and attaches the skeletal meshes/blueprint to the feet of the character instead of the defined socket .