The byass, I would recommend buyint the valve mounted bypass. Gate valves are not considered the most reliable design. If you had a high quality 3 valve (Apollo, nibco, etc) ball valve bypass, then I would not be concerned. Shark bites will work, but you are still going to have to solder out of the gate valves to get it to either threaded or a piece of pipe.
The drain... anyone else want to comment on that? Not my preferred drain. Since an air gap is required. Not to sure about how well these work, someone posted what appeared to be a better design a while back.