Since the property was vacant for a portion of this time, the tax rate was multiplied by a factor of 10 ( as per DC vacant property tax regulation ) which explains the cost of the tax lien.

This is calculated by taking the Base Loan amount of $173,700 and multiplying it by 1.75%  (.00175 x $173,700 = $3,039.75 - this is the UFMIP) -- then add this $3,039.75 to the Base Loan.The Annual MIP which is actually added to the monthly mortgage payment (1/12 each month) is calculated by multiplying 0.85% (.0085) by the Base loan amount of $173,700 and then divide that by 12 to get $123.04, not far off from your $115 estimate.

is the $400 negative divided by 3 or multiplied by 3?

Multiply the price in #4 by .65 to .75.

If I turned the water into a monthly expense then I would have to convert all of the expenses to a monthly rate and then multiply by 12 to get the annual.

Here are the numbers for the property:OverviewMonthly Income: $900.00Monthly Expenses: $961.09Monthly Cash Flow: -$61.09Pro Forma Cap Rate: 3.54% NOI: $2,016.00Total Cash Needed: $16,225.00Cash on Cash ROI: -4.52% Purchase Cap Rate: 3.54%Property Information Purchase Price: $56,900.00 Purchase Closing Costs: $2,000.00 Estimated Repair Costs: $0.00 Total Cost of Project: $58,900.00 After Repair Value $56,900.00Down Payment: $14,225.00 Loan Amount: $42,675.00 Loan Points: $0.00 Loan Fees: $0.00 Amortized Over: 30 years Loan Interest Rate: 5.000% Monthly P&I: $229.09ExpensesVacancy $54.00 (6%) Repairs $90.00 (10%) CapEx $198.00 (22%) Insurance $100.00 (11%) Management $90.00 (10%) P&I $229.09 (25%) Property Taxes $200.00 (22%) Total $961.09 (107%)Financial Projections Total Initial Equity: $14,225.00 Gross Rent Multiplier: 5.27 Income-Expense Ratio (2% Rule): 1.53% 50% Rule Cash Flow Estimates Total Monthly Income: $900.00 x50% for Expenses: $450.00 Monthly Payment/Interest Payment: $229.09 Total Monthly Cashflow using 50% Rule: $220.91

There's a multiplier effect with rehab work, that you'll really come to appreciate as you do more of this.

There are people on here warning about that sort of thing all the time, and being completely swamped by an avalanche of "You go, dude" comments. 

Divide that by 365 days to get your daily rate of $57.05479 and multiply that by 30 days (month) to get $1,711.64.

The electricity and water required to do a load of laundry multiplied by the number of Tenants per week will add up very quickly.