They will need evidence of the borrower’s death and some type of authority to talk to you or the PR.

You will need to get the borrower's permission to contact the current lenders to find out that info.

As an example, I plan on borrowing $130K, 20% down, 5% APR.

That kind of borrower profile is what keeps everything moving and pulls us through the hard times.

Second, those who retain servicing are concerned with capacity to process loss mit and loan workouts so they don’t want any investor loans or loans secured by the primary residence of investors because, statistically, investors are more likely than less sophisticated borrowers to strategically default.

You can make your down payment and immediately borrow against it, and that is about the cheapest money available. 

Ultimately, I borrow from my TSP to invest in short term flips.

If you borrow the money, you're more likely to over-spend because you'll have your reserve to dip into.

When you invest in RE deals you borrow from the cash value, and still get your own interest on the borrowed amount but you have to pay yourself interest on what you borrowed (not sure what the Dividend/Borrowed delta is). 

Suggestions:1) get good rental property insurance that covers loss of rents for covered reasons: fires, etc; 2) be a good landlord and treat your tenants as customers you will reduce liabilities with an ounce of prevention; 3) Get umbrella insurance which also helps to covers your assets in a suit; 4) IF you get an LLC you must run it as a separate business or it will not provide you any protection (I'm not an attorney, but that's my understanding); meaning if you combine your business funds with your personal funds, they will be able to demonstrate it behaves as a straw company and really the courts should ignore it as a separate legal entity (my understanding of the risks).  5) LLCs can make lending/borrowing more difficult, until you want to borrow non-conforming loan funds (non-Freddie/Fannie) or you hit your 10-15 property limits with Freddie/Fannie, at which time you'll need to go to commercial lenders who will WANT the property/loan to be in an LLC.  6) As you grow your portfolio keep in mind conventional lenders will look at your DTI (debt to income) ratios.