Character modelling - posing practices

Hey so I'm currently modeling a character and I'm a bit stuck because I don't know how to approach posing him. He is wearing a long robe sort of thing and should have his hand on the head of another (smaller) character. Should I model out everything in T-Pose and then rig him to the pose I want? Is this standard practice?
I feel like whatever the case i might need to model and texture the cloth after once i used Marvelous designer or something similar to get nice folds from the pose