Sister's rent amount, term (date of refinance), mortgage payment responsibility, insurance responsibility, utilities responsibility, tenant selection responsibility (since this will be a multifamily property), property management responsibilities including repairs, maintenance...2.

The loan balance becomes higher because lender is including closing costs and escrows into the loan amount .

In today’s high rate market, 1% ratios do not cash flow at high LTV in most markets.   50% expense ratio $2550. 80% financed at 7% (OP indicated and does not include the plumbing) P&i $3,332/minth. $5100 - $2550 - $3332 = -$782/month after achieving market rent.  

It is a balance sheet of all of your assets and liabilities including both personal and business. 

The ADU did a site visit, and the takeaways included adding a second story would be significantly more complex and expensive than a backyard ADU.

I'm considering hiring a company that will meet with me and design our flips from studs to finished product, including the functionality of the property to the actual finishes used; i.e. the design of the flip. 

Quote from handy Man/Contractor around $25,000 not including windows. 

I agree with Jacob, about 150/sqft - that includes finishing a basement too.

Are property tax and insurance deductions included within their study?

@MJ S.If a borrower goes into default they will get desperate and do anything to stall including filing a wrongful foreclosure suit.