As that wise fella said. There is only two ways to do things--your way and my way. There is no right way, best way or wrong way. Do what works for you. How much ammonia is produced by 10 danios? They know, do you?
Not sick, just a fact. Urine can contain some small viruses as well.
There was an importer on this site who said he had used urine to do a fishless cycle prior to importing.