Looks like you guys are definitely on the right path. I like the tank design with the custom cutout for the pump. My pump and solenoid are located under my tank as well but my tank is a complete rectangle so no cut outs.
He ran my wmi lines underneath the car near the fuel line all the way to the motor. A good rule of thumb that I learned from him is that this is a "heat friendly" path to route the lines while keeping them away from the exhaust and such. I know some people run the lines through the car but I'm personally not a a fan of that.
Pretty tight underneath my tank for pics but this is the best I could get. Also posted a pic of where my controller is mounted for possible idea purposes for you. I also received this custom CF bracket as a gift as well.
Oh and I'd suggest doing some deep research on what nozzle size to use. This took a lot of trail and error for me as I originally started with Snow Performances #4 nozzles before upping it to the #6s. Much better flow as the #4 are 250ml/min VS 375ml/min for the #6 nozzles. You're using a different WMI kit so the nozzles size may vary but still something I'd pay close attention to. I've talked to some people who run even bigger but the last thing I'd want to do is hydrolock my motor. Plus I'm running e30 so I can't go too crazy here..
Good luck.
Edit: Also longer braided lines. The gran coupes are far from short so we ended up needing to get longer lines from Summit Racing. Only 30 mins away so wasn't too much of a hassle.