Now, here is my solution. I can create a private key using 20 words. And I can make the last 5 words something only I know. I can email my family (and myself) the first 15 words. Then, I can email them the clues of my last 5 words. Of course, I have to do a damn good job that only the ones I fully trust know the answers. So, I guess my method is 3/4 paper - 1/4 brain wallet?
This is a terrible idea.
You should never store your seed, mnemonic, passphrase, password, anything online, and especially not on something as horribly insecure as an email server. You are essentially making your first 15 words public.
You have now reduced to security to 5 words. These 5 words are picked by you, and so not truly random. Since you are storing your first 15 words and your "clues" on the same insecure email server, if someone has access to one, they have access to both. You are also essentially making public "clues" to these 5 words. This is probably going to be both brute-forceable and maybe even guessable.
Even if you picked 5 truly random words (which no human can do) from the entire subset of the English language (approximately 200,000 words), then you still only have 3.2*10
26 bits of entropy. For comparison, a 24 word seed phrase has 1.16*10
77 bits, meaning your set up is somewhere in the region of 1000 trillion trillion trillion trillion times less secure.
There is a reason there are near universally accepted "best practices" for storing your keys - they work. Use a BIP39 compatible 24 word seed, write it down on paper (never store it electronically), and hide it somewhere secure.