***Suppose, you got 4:2, corresponding to stable neutrino systems (or systems made out of other unstable in our world particles which happen to be stable at 4:2 ratio of constants, so to speak) The systems evolved to self-reproduction and thus satisfy some definition of "life". Later they evolved to intelligence, satisfying definition of "observer". Do those observers deny other combinations of fundamental constants because they result in different "kinds" of observer?***
No, different values of the constants do not restrict other observers in other universes with those different values. The issue is whether you modify the current constants and still see a universe capable of evolving observers (first life then observers). The answer from physics is that it is apparently not possible to appreciably modify the physical constants and still expect to see large size structures (which is absolutely necessary for any kind of evolution). Read the paper. There are more papers as well.
***So, more logical than SAP principle (let's call it Super-SAP) looks like following: (1) There exists at least one possible Universe containing at least one kind of observers. (2) Observers are not necessary to bring the Universe into being. (3) An ensemble of other different universes is possible, although not needed for the existence of our Universe.***
This does not offer any kind of explanation. It is redundant. We already know that there is one possible universe containing observers because we happen to be living in one in which we are the observers (sic). We also know that an ensemble universe is at least conceivably possible, so that doesn't state anything novel either. Number (2) is contested by some who have a peculiar interpretation of QM, but I wouldn't contest (2). But, your (2) seems to be unrelated to what you want to say. What you really want to say, if I'm correct, is that WAP is enough to 'explain' our existence. But, you haven't replied to the paper that I posted that tends to refute WAP (and there are more which I didn't post just so that your attention can be more focused).
Warm regards, Harv