You don't have to fix toilets or see if the tenant is mowing the lawn.

All cpvc capped and we shoved a rag in the toilet sewer line.

I am looking for a contractor to install a bathroom (sink, toilet, shower) using the upflush system and closet in basement.

If you go for adding a bathroom consider splitting the shower from toilet sink.

3) Toilet?

I am looking for a lease for a SFH whereby the tenant is responsible for tenant activities (such as you clog a toilet or break a door or window, you fix it or you pay to fix it), but I am responsible for landlord stuff (broken water heater, etc.). 

Higher ongoing costs - you are paying all utilities + Netflix/cable, you provide toilet paper, coffee, cleaning supplies, etc that are not included with LTR.  

If you look at the long term rental calculator it can should break down all of the expense categories but here are some expenses you need to plan for: Maintenance (ex: calling a handyman for a broken toilet), capital expenditures (roof, hot water heater, HVAC), lawn care, insurance, property taxes, management if you are not self managing, vacancy, and more.

LOL I don't earn squat on my regular savings account at my bank, but keep my larger opportunity fund in Vanguard.

Ther are certain toilet papers that are better for septics (a little less comfortable on the bum) but good luck enforcing that.