1-3. You still need to know the word list but it could be changed in a way that doesn't depend on a fixed length word list like the algorithm Electrum uses
4-6. This can also be implemented but it would increase the number of words and the result will no longer resemble a normal BIP39 mnemonic.
My idea was an attempt to end up with a result that doesn't look any different from regular seed words.
I need a way to store more information than just the seed words. For each wallet, I figure I might need upwards of 1000 characters. Possibly I'd like to store multiple wallets all at once. So looking at maybe 5000 to 10000 characters. 10 kb. I need to be able to print out an encrypted image on a piece of paper. That would be my cold storage. When I'm ready to redeem, I will scan the image back in and decrypt its contents. And recover the original text file containing all my important seed phrases. I think this would be more secure than putting it on a flash drive since paper can last longer. Hundreds of years. then only problem is that you can't really use qrcodes for that. they would literally be huge.
Or i might just have a need to encrypt a text file containing 1000 private keys. That might require 2 pages.