Cleveland investors often aim for COC returns of 8–12%, so you’re in the right range.Net Cash Flow: $277/month is positive and provides a buffer for unexpected expenses.

Say, 3 month later, I decide to do a cash out refinance of the replacement property at 75% LTV because the rate is lower. 

Seems like it could be pretty easy to throw in an electric one, no?

To avoid the risk management/insurance that comes with tenants' wood fire use:I'm thinking to seal the chimney cap on roof and run a cord putting an electric Infrared heater fireplace in there, so they can still open the glass and get heat and watch TV over the mantle, but can't burn anything or have any flame.

The maintenance and cap ex will kill the cash flow at that low a valuation.

Then don't rehab for zero COC return.But if you can spend $3000 on the lite rehab and increase rent from $1000 to $1050 then you'd gain $50 per month.50 x 12 = $600 more annually because you rehabbed.600 / 3000 = .2 or a 20% cash on cash return! 

I've been doing a deep dive looking at cash on cash return for various down payments and expenses on properties with a mortgage.

Quote from @Gary Aragon: Quote from @Rick Albert: Our electricity is already separate and we designed our ADU to be all electric so no gas. 

In the Parlor floor we added a large-ish kitchen with electric oven and cooktop that goes to the sub-panel that belongs to the Parlor floor, making it a nice 800ft 1 bedroom apt, with access to a shared backyard.   

My only cash investment would be the 10-15k of closing costs as of right now.