The character rig is pretty nice ive brought some of those daz/poser models in UE4 in the past but theyre pretty bulky… Remove any joints u dont need and do a reskin. Ive built a small script you can use to rename the joints to standard motion builder naming convention for sinple retargeting ill find shortly. To fix all the issues with multiple texture maps that may exist on your model, bring the model into zbrush and convert texture to polypaint, then adjust the uv maps on the mesh and then apply the polypaint back to texture, just a tip.