Thanks for the thorough reply!

I do acknowledge that funds are often lost by the user, so I have been careful to err on the conservative side when setting this up, trading off security for redundancy. I stayed a year with this setup while having the words loaded in a hw wallet too.

I see 12 words + encryption passphrase as one unit, because they're always kept together. That is stored in 3 physical locations as I mentioned.

The other 12 words (2nd piece out of 3) are kept in 4-5 digital locations.

The encoding method is also stored in 4-5 digital locations. It is also easy enough to remember, so can be brute-forced by me if I forget the exact details of it. I think this solves B) pretty well.

As for A), I think a replication factor of 3 is sufficient - although I can certainly improve it a bit further (e.g even bank custody) given that even those words can be encoded. The encoding I really like because it opens up a lot of practical applications that I otherwise would have been uneasy to do (e.g storing plaintext 12w at a bank, at a friend's house, etc.)

Thank you, I will research more into that and really dive into Lopp's post -- this is the second recommendation now.