Hello, glad to help.
Their hose is actually Russel if I remember right. If its not that its earls. So considering that passes, I believe you are good. I still prefer braided for a track car, but thats your call. On something you drove there for street class...I doubt you will get any flack.
Yes you can keep your box. Somewhere a few pages back I posted the wiring diagrams. Its one of the options.
Your last one is a bit more technical, as its a little more than just a fitech question. I would never, ever run an evap kit into a full exhaust. Thats asking for oil to pool in your mufflers, and even excessive "sucking" oil out the breathers.
But...the sensor wont like being downstream of an evap, or being within 18 inches of the exhaust end, and also needs to be ten degrees off the horizon.