@Matthew S. I'm glad that this was helpful. To answer a few of your questions.
I would leverage his W-2 and buying power now while he has it. As you stated, in 2 years he will be retired and much, much harder to get a conventional loan. Additionally, having cash on hand is much better than having equity on hand. You can't eat equity. It is mostly a personal choice/situation and you have to feel it out. But there are many ways to skin this cat. If need be get your 10 conventional loans first and then figure out how to refi them all into a blanket mortgage and start over.
So, making sure that the financing works for you and not against you. As many gurus out there say "you make your money when you buy." I find this to be mostly true, but with the caveat that "you make your money when you buy with the right financing."
A great deal is a great deal, but bad financing is the fastest, and most common, way to kill a great deal. We should all know how to calculate the cap rate so I won't go into that. Investopedia defines the loan constant here. Essentially, this is the inverse of the mortgage payment. It is based on the interest rate of the loan, the duration of the loan, and the compounding factor of the loan. For instance, an interest only loan of 7% has a loan constant of 7%. But a 30 year fixed loan of 7% has a loan constant of 7.98%. And a 15 year fixed at 7% has a loan constant of 10.79%. So, if you were to go out and get "the best 15 year mortgage" out there as many gurus suggest to get rid of the debt faster you would actually get rid of it much faster. Because you would lose your shirt and the property! You have to know your spread. spread is calculated as Cap Rate minus Loan Constant. If it is negative you are in trouble. If it is positive you have a chance if you manage it right.
So, if you had on the same property a cap rate of 7% the interest only loan would be neutral to you at the end of the day. Not great, but not bad. Any volatility in the property would be dangerous if not disastrous to you. Now the 30 yr fixed is nearly 1% negative. So you are going into the deal at a disadvantage. This is where knowing your numbers is key and making sure you have reserves. But, if you took the gurus advice, and got the shortest term financing out there you would be nearly 4% negative! Any tax, inflation, cash flow, etc advantage you think you are going to have is going to be eaten up from the moment you sign on the dotted line.
Now some may say that 7% is high. Ok. I'll give you a phenomenal rate of 4% on a 15 year fixed. You know what? I still wouldn't do this loan because the loan constant is 8.88%! Still 2% negative on the deal! And you are on the hook for the full PITI if you have a vacancy. The larger the spread is, the higher volatility you can handle in your asset.
That got a little long, but I think that this is a very important point that nearly all investors I've talked to miss. The deal has to be good, yes. But how you pay for the deal is more important. There are three sides to every deal, the asset, the capital to buy and the finance structure. The way you structure the finance is probably the most important of the three, and the least understood.
And last, bummer about the inherited place. But if you aren't going to pay taxes its good. Just be careful about repatriating money and any tax consequences that may bring. I think that the same concept still applies though where you can use that money as a good portion of your emergency fund and reserves and the rest used as down payment money on financing for turn key rentals.
Good luck!