3016 is very acceptable for JA (in fact it's the standard), i've broken the 8k barrier on some experimental models so no need to worry about optimizing more, plus the processing power we have now doesnt have a problem handling higher res meshes.
I think you should add the belt as a separate piece of geometry, simply create a cylinder and position it where it should go. Open geometry is fine in the engine.
Be careful not to remove too much geo on the cloth near his legs, one thing that works well for this is to match the underlying geometry to make sure the cloth will behave and follow the movement like the hips.
I dunno if the boots are based on a real design but they feel kind of goofy, the bottom part, make sure you get good reference and tweak accordingly.