T@B 320S Isolation Valves

newell

     I just finished winterizing our 2017 T@B 320S from our 3rd. season.  Every year I wonder why they arranged the outdoor shower valves the way they did.  In the summer valve positions, you blow out the water and drain the pipes and then put the valves in the winter position and add the RV antifreeze.  After introducing the anti freeze you're supposed to allow some to run out of each faucet to ensure the pink stuff is actually there in the fixture.  With the valves in the winter position, you can only run the cold outside shower faucet.  Trying to run the hot only backfeeds into the hot water side of the Alde.(See Photo 1).  Is the long PEX fitting behind the hot water isolation valve (See Photo 2) a check valve or some kind of back flow preventer?  There is one of these on the cold water side too.  It seems like the hot isolation valve and the "tee" going to the hot side of the outdoor faucet should be reversed so that both sides of the outside shower could be bled.  Any thoughts from you engineer types?