Hi FTT, I smiled to see you offered a choice to your siblings to be a beneficiary. I guess they might decline if they don't need or want the money.
It's a very smart move, because pay on death beneficiaries get their money directly without any interference by the executor or probate courts.
This thread reminds me to keep plugging away at my end of life, seriously ill papers. Next up will be my medical directive and medical power of attorney. The model I found was quite detailed, and as I have developed a love of methods the medical profession looks askance at, I want to provide my POA with latitude and permissions, even specific specialists, for various scenarios.
My future worry is finding an attorney to look it over. It's enough of a risk to write this out, I don't want to have to struggle with an "expert" (and pay for the privilege) nor do I want derision (and pay for that, too!).