Not sure why you think those keys have a backdoor. 14551231950b75fc4402da1732fc9bebf is what you get if you pick (2**256-1) as a private key, which is above the group order, so mod 0xfffffffffffffffffffffffffffffffebaaedce6af48a03bbfd25e8cd0364141 it becomes 14551231950b75fc4402da1732fc9bebf. Likewise, ebaaedce6af48a03bbfd25e8cd0364141 is just the group order with the upper 0xfffffff... removed.
I don't think N was chosen intentionally having such backdoors, but I do think those keys I mentioned could help in solving low range keys only if we know the exact starting/ending range.
Though my fascination about this one 14551231950b75fc4402da1732fc9bebf is different, because some people might think every key will result in some specific value when divided, but the key above is the evidence of how wrong we could be sometimes. Just like when you divide that by 2^255 mod n, you'd get "2" as the result, of course once you know that, it's not anything interesting, that's why I'm eager to learn more about other similar keys with similar properties.