No. You can pose and animate it with the normal Blender tools. Auto-Rig Pro is only useful if you want its retargeting or export features.

Each clothing mesh has its own fatty, builder and skinny shape keys. Set the same value on each piece, or add one driver from the body shape key to the others.

The FBX and GLB include the skinned mesh, the rig and the shape keys. Engine setup (humanoid avatar, retargeting) is up to you and has not been tested in every engine.

In the .blend file the textures are packed, so this should not happen. For OBJ, unzip textures.zip next to the OBJ and MTL files.

Yes, under the Royalty Free license you can use it in commercial projects. You cannot resell or share the model files themselves.

It comes in T-pose without animations. Use your own animations or a retargeting tool.