Hold that thought
Characters and items mounting systems and tools have to be set up properly for seamless iteration and integration efforts throughout production. Vehicle mounting and animations are kept generic for flexibility in character role assignment. Items and weapons can be held in different ways. On the Maya side this means locking one or both hands on the weapon, with the ease to change the holding position on the weapon.
After designing and prototyping the rigging framework for characters and items proofing smooth transitions between authoring and integration, I built Maya authoring tools for rigging and animation, as well as event triggers in Unity for mounting.
Mounting characters onto vehicles is a separate complex ordeal, especially in the authoring environment. The two primary goals are to visualize multiple character interactions and keeping the target character at the scene origin. This means the vehicle is reverse-mounted to the target character (at the origin), while referenced animated characters will mount to the vehicle.