True Random Numbers: Yes, you can, just mix-up all provided letters in a hat (over 216 bricks will be enough even to build a Master Seed) - and pick it up. You can make true random lottery
Safe deposit box: You can have one in your basement or you can have one inside Goldman vault...
Anycryptocurrency: it not easy to find a nice paper wallet generator for example for YBCoin - yes, you can print it, So I will fix it in my chart. Thank you
True Random Numbers: While I hadn't thought of drawing a key from a hat, it still can't be truly random unless there are more of each character than can possibly be used in the key, for instance, it is possible for a randomly generated key to consist of one character repeated as many times as necessary just as it is possible for enough monkeys with enough typewriters to generate the works of Shakespeare. IOW, because there are constraints (i.e. no more than 4 of any given character), it is not truly random. One could even argue that method of mixing the bricks in the hat tied with the different weights of the bricks and followed by a human drawing the bricks from the hat would significantly reduce randomness, but that argument isn't necessary due to aforementioned and much more significant constraints.
Safe deposit box: Yes, and the one in your basement would not have any more third party risk than the cryptosteel, but a cloud-based storage solution certainly would (even if the risk were loss vs theft).
