3D Modeling in Blender for UE4

There is a set of 3D arms with a skeleton and animations in Unreal Engine 4. I will need those arms exported from UE4, and imported into Blender. Those arms will need to have sleeves added to the arms. They will need to be from a military uniform (image attached). 1. The arms will need to have the mesh modified to make it look like it has long sleeves on. 2. The arms will need to show working animations in Blender. 3. The modified model will need to be exported from Blender, and render and animate correctly in UE4 4.20. The following files should be created: 1. File of the original arms working in Blender, saved as an FBX file with working animations. 2. Modified/New arms with clothing saves as FBX with working animations.