Definitely a question for a tax attorney/accountant, especially with the dollar amounts involved. 

Are they going to be able to buy your proudly done flip.3) If you misjudge the market, do you know when to dump it.4) Can you put a spreadsheet together on your purchase costs, carrying costs, rehab costs, closing costs, selling costs, tax costs, contractors that don't show and delay your project etc. etc. etc.5) Is the return worth the risk.

Make sure to plan for the added rental income/ordinary expenses on your tax return. 

you just input the address and it import the information which has bedrooms, bathrooms, and square footage. just be careful with the insurance and property tax data.

Just guessing the numbers.If we put down $400,000 together with an interest rate of 7% (it could be higher), then im guessing the monthly mortgage with insurance and tax would be around $3,886.If each unit rents for $1,500/month: Total Monthly Rental Income: 1 , 500 × 4 = 1,500×4=6,000 Monthly Expenses: Mortgage (PITI): $3,886 Maintenance/Repairs: $500 Property Management: $600 (10% of rent) Vacancy Reserve: $300 (5% of rent) Total Monthly Expenses: 3,886+500 + 600 +300 = $5,286 Monthly Cash Flow: 6,000−5,286 = $714We split the profit in half so each person takes $357 a month..How much should we be profiting from this in order to make it attractive to jump in? 

I own 19 properties in Rhode Island and have found the Eastern CT market to have Rents just as high as Rhode Island with property prices 60% less and taxes 50% less.

Seller says they will accept $300,000 down (non-refundable) with lease payments of $4,500/ month (doesn't count towards principal) for 3 years in which we would have to pay the remaining $1.45 million at that point (title stays in seller's name until then and also pays the property taxes).

No DTI, No Tax Returns, just wanted to see that the rent can support the proposed mortgage.

They can really throw off your numbers if you are not familiar with a citys transfer tax, and fees.

If you need financial help, ask under the "Finance, Tax, and Legal" forum.