I know my husband would not go to the same lengths I go to to make the most of our money due to lack of interest. But on the other hand, I still keep him well informed of what I do, even if I spare some details.
That said, I don’t intend on micro-managing what he’d do after I died. First because I trust him to mostly not screw up. And with my life insurance policies, there’d be a little bit of leeway not to optimize his finances. So he’d probably go to a much simpler setup like: one single cashback credit card like Citi Double Cash), one single online savings bank (like Discover, Citi, or Capitol One), and one bank with local branch for checking.
Ultimately, our shared password manager is about the extent of my instructions to him. I have notes for each bank about type of accounts, routing numbers, account numbers, etc to go along with the randomly-generated passwords. He already can check almost all our accounts in Personal Capital. So it’d be easy to go about the ones in my name only and talk to these banks about my accounts.
My main concern has always been however what happens if we BOTH meet a very sudden death. Our kids are not old enough to be trusted with all our information. So our current solution centers around using a safety deposit box at a local bank to which our executor (and his backup) would have access to after we died. The idea of an electronic dead-man switch is somewhat appealing but in practice I have not found anything I could trust to cover all our bases.