Aim small miss small.Love the comment about taxes, that's helpful.

I have to reserve judgement until I know what price point you're aiming for and whether it's a flip or a rental.

We have also read quite a few different things regarding how many buyers you should aim to have.

You need an analyzed NOI and sales price to have a property specific cap rate since all it measures is what the NOI SOLD for, not what the seller hoped for based on their NOI and asking price (CRAP RATE). 

The aim is to avoid liquidating any real estate to pay estate taxes, small debts etcThanks in advance

I am aiming to purchase my first rental property a duplex or triplex.

I would never ever consider it in a state like NY were foreclsoures are measured in years not months.. this is a financial disaster.If the OP does not care about his credit and thinks the lender won't go for a deficiency then he can just walk away.. although he may end up with a 1099C and have to pay ordinary income tax on his debt relief.. this is how I am seeing it.... unless he posts otherwise. 

2) What is the best type of tenant group to aim for (professional vs section 8, etc.) ? 

Six months for rehabs might be a bit much, if you research your deal properly, which it sounds like you intend on doing.You should stick with your goals, aim to get the work done in 2 months.

Be Smart, S.M.A.R.T. refers to goals that are Specific, Measurable, Achievable, Realistic and Time Framed.