The result
Only 1 of the 66 pairs agree on even their first character. Every other pair differs at position one.
What a small number rules out
A set of addresses built to look like each other would show long shared prefixes, because that is what building lookalikes means. Somebody grinding for a family of similar strings would produce four, five or six characters of agreement, and it would show up here immediately as a run of pairs with long matches.
Nothing of the kind appears. The twelve diverge almost instantly. Eleven of the twelve share nothing at all with any other address in the set, and the single pair that agrees does so on one character, which is roughly what pure chance predicts for twelve strings drawn from a 32 symbol alphabet.
So the set behaves like twelve independently generated addresses. That is a real finding and it is worth having, because the alternative would have been visible and is not there.
What it does not rule out
It does not rule out that one of the twelve was inserted by somebody other than the publisher. An inserted address generated normally would look exactly like the others, because normal generation is what produces this pattern. The prefix analysis catches lookalikes, not additions.
It also says nothing about where any of them leads. Twelve strings can be statistically perfect and lead to twelve different places, or to nowhere. Character analysis reaches the shape of the set and stops.
The trap to avoid is treating a clean statistical result as a verification. A clean result means nothing about this set is suspicious. Somebody wanting to be believed would produce a clean result on purpose, and it would cost them nothing, because the cheap thing to do is exactly the thing that looks innocent.
How the comparison is done
For each pair, characters are compared from position one until the first mismatch. The count of matching characters before that point is the shared prefix. It is computed on every page load from the twelve strings, over all 66 pairs, and every record page reports the longest agreement its own string has with any other.
Where a forgery would differ instead
Questions
Would two similar looking addresses mean one is fake?
It would mean one of them was probably ground for that resemblance, which is a reason for caution. It is not proof, and the absence of resemblance is not proof of the opposite.
How many pairs are there in a set of twelve?
Sixty-six. Each of the twelve is compared with each of the others once, which is twelve times eleven divided by two.