It will become my primary residence while collecting rent from the business portion, so I’m not too concerned about the cap rate while I live there.

Originally the seller wanted to finance more with us, but due to his own tax situation he just did the down payment portion.

This quote was to remove and replace approximately a 15' x 15' portion of that area. 

Fair market rent for my portion of the house is around $2,950/mo.I did part with $109k down payment (including closing costs), but I've been saving for quite some time so I still have some fairly healthy cash reserves, and I'm actually looking get another property within the next 6-12 months (most likely out of my expensive market though). 

Or will New York immediately, or sometime in the future, want their portion of tax on the gain? 

Does it mean that I have only 75k of my non-taxable money and 200k portion is kind of income that I need to pay a taxes?..

I would like to ideally rent out the basement too so it covers a portion of my taxes/hoa/mortgage.

The husband would like to get his portion of the security deposit since he's been kicked out and no longer living there.

In return, they would theoretically agree to sell us the house when they're ready.Mom & sons continue to live there until they decide to sell (likely soon to pay for college) or until the divorce forces the sale.Once they are ready to sell, we buy it at a discount & flip it.Alternatively, maybe we buy out the husband's equity in exchange for part ownership in the property, then buy out the wife's portion when they are ready to move. 

If you paid for the placement, I'd try getting a portion back based on the fact they didn't properly screen.