At 16 and 13 years old, I would not be worrying about YOU predeceasing them.

Now, add the fact that your cats are all very bonded. I say that as long as they have each other, they could make the transition OK.

I will add though, that I know of people who have cats that this WOULD be the correct plan of action. Semi-ferals, for example, cats who have only learned to trust their one and only human, would probably have a very difficult time adjusting.

So in your case.....NO, but there are cases where I would suggest differently.