The Ammonia will spike, just wait... once it does continue to test and you will see Nitrite rise, then Ammonia and Nitrite will start to fall. Once you see Nitrate present, and Nitrite and Ammonia are 0, you're ready. All tanks are different, some will be a week, some will be months. I'd recommend pulling the shrimp out if you put it live rock - the shrimp method will produce Ammonia, but it's not necessary and will start you out one step back IMHO. If you want to seed the tank use a bottled bacteria such as Prodibio.
FWIW, peeing in tanks isn't that far fetched. Back in the day prior to having different forms of bottled Ammonia redaily available Tridacna clam farmers would pee in tanks and it excelled growth like no other ;) Not kidding...