That toilet isn’t a lot different than just using a 5 gallon bucket. I separate the water myself with another bucket and do the same thing. Water my garden with the diluted mixture. Works great, especially with a hand full of wood ashes. Trees grew almost a foot last year.
Love your tiny house. Its ingenious how you sunk in the tube and thats its multifunctional and a shower and bath. Really cool how you just stuck the fan behind the mirror. Was that glass or reflective metal? We may go a similar route in our tiny cabin once we build the add on bathroom?