It can trigger the "due on sale" clause and a lender could demand you pay the loan balance in full.

For signing a contract to purchase this house, should the seller's name on the contract be only the widow? 

@Michael Garfias You should research the surrounding areas to see where the residential MFH (2-4 units) 1) are available; 2) in demand; Once you find your target market, determine how much would you need to buy it.

You are basically purchasing a 100% vacant stand alone building, make sure you feel confident on who your future tenant is and that there is demand for the space. 

The advice I would give is to find some wholesalers to source deals for you, source your own deals via direct mail or phone calls, and also work with your agent on identifying deals and crunching the numbers to make sure they really work before writing any offers or contacting the seller to see if an offer can be made at whatever price you are thinking of offering.You and your agent should be a team and should be working together on doing what's best for both of you.

In the interests of brevity I'll get right down to where I'm at:- I am educating myself, starting to network, have started looking for deals and swapped numbers with some sellers- I have capital - I own a home overseas (through an inheritance) that will get sold - educating myself for this sale was how I stumbled into Rich Dad... woohoo cashflow 101 classic online game mindset changer!!

My Name is Zarhar and I am new to investing,  I have a potential deal with a seller who is trying to get a duplex off his hands.

Yes, determining demand would be the first step in any business venture.

Made an offer on a property that matched the seller's asking price.

I don't think Jefferson Park has a lot of demand for short-term stays.