Just gotta do it the way every other investor does it by subtracting your expenses from the projected rent and the difference is your cash flow.

Whatever you took the original loan for subtracted from the current limit is what you have left.  

Subtract.

Or if for example you were going to offer $300k, I would get estimates on installing a new roof and then subtract that off your offer.

Does not reporting the expenses mean I have a higher taxable income from which lenders will subtract my debt?

I think you need to look at what comparable lots are selling for and subtract the demolition cost from this figure.

If your cash flow available for distribution for that year is greater than the product of (pref x beginning capital), you'll subtract it from your beginning capital.

My understanding of NOI is if there was no borrowing involved and we payed all cash, took the total income (which would account for vacancies already), subtracted our 'expenses' such as minor repairs, snow and grass, insurance, utilities, etc..... you would have your NOI.

Get a quote from a local property management company to see what the average rents would be in that area and then take the rent, subtract all of the expenses and see what your left with.

I can’t recall if you provide the exact window hole size or subtract a bit off when you provide the measurement.