Your heater does not have an anode rod. Mine doesn't but I can't remember the brand. The picture is the same as mine, no anode.
As far as the bypass goes, the water enters the HW tank at the bottom and exits at the top. Follow this route and look at the valves. In your picture the bottom valve is "open" which allows the water to enter the HW tank. You don't show the valve at the top. If you were to change the bottom valve it would not flow into the tank but go up the bypass pipe. IF the top valve is parallel to the pipe coming out of the tank, the water will not go anywhere. So, if they are both horizontal, the water will enter the tank and exit at the top. If they are both vertical it will bypass the tank. I think this is your situation.
As far as the leaking fresh water fill, that is what is sounds like. Where the fill connects to the fresh water tank the water is leaking, especially when you fill the tank and it backs up. If you can gain access to the fill door from inside you should be able to see the problem.