Thanks for the references, but in them you answered only the second question—how this fits with reality. But not the first:
“1. How do we know that God is good? (I assume that from any empirical finding we could just as well suppose that God is evil but does a little good, just as much as the reverse.)”

I don’t know of very convincing arguments for His goodness. I’ll give the main considerations here:
1. He and His prophets simply told us that He wants what is good for us (that it may be good for us all our days).
2. Beyond that, there is an assumption that what is perfect ought to be good.
3. Beyond that, the creation of the world brought some creatures into existence for no apparent reason, and apparently He wants them to exist. It doesn’t seem that their existence serves only as an instrument for abuse, and so some have concluded that He wants to bestow good upon them.

4. Perhaps one should also add His commandments and the rebukes of the prophets in His name, which generally testify (though not always) to a desire to do good.

Doesn’t that undermine the basis for serving Him? Maybe He commanded me to kill Amalekites not for a good purpose? And then I’m obligated to a morality to which He too is subject.

If you reach the conclusion that He is not good, then there is potentially a challenge here to one’s obligation toward Him (though some would say that His commands still have force because He created us and the world, or because of reward and punishment). But when there is no proof, that doesn’t mean the thing isn’t true. Consider what I wrote above—and reach your own conclusion.

Just one more comment. If He is not good, then morality too has no validity (see the fourth notebook, part three). Maybe that is another proof of His goodness: that He implanted in us a moral sense and a sense of obligation toward it.

Sorry for jumping into the discussion. The answer that there is no better system of laws available is not clear to me. That limits the Holy One, blessed be He (what, can He not create any system whatsoever?). And certainly there is no logical contradiction here or anything irrational: simply a system of laws without the possibility of natural disasters or diseases developing.

Apparently there is some logical limitation here which, because of its complexity, we do not understand

Indeed, God is prevented only from doing logical contradictions.
Once He has chosen to use a certain system, there may be limitations that are logical by virtue of the system’s definition.
And in our case, God chose to run the world according to fixed laws. If there were local interventions, then by definition we would no longer be talking about laws. A law is by definition blind to contexts that are not physical (but rather utilitarian, moral, etc.).
If some iceberg melts, it is supposed to fall downward, even if there is some unfortunate person who will be killed by it.
The law of gravity is supposed to be blind to contexts that are not physical, and therefore God had two options before Him: 1. to create a world without rigid laws (= an iceberg that sees there is a person underneath it will not fall downward), 2. to create a world with rigid laws (the iceberg notices nothing beyond physics).
Since God chose a world with laws, it follows logically-conceptually from that that there will also be bad things.
That is how it seems to me.

Well answered.

Y, you’re right that it’s impossible to make a perfect world, and by force of the laws there certainly can be bad cases. But there are a few things that are not a private case, but something major that is really part of the system. For example: the development of diseases (couldn’t a world have been created without the possibility of a cancer cell?). Or natural disasters (couldn’t a world have been created without hurricanes and tsunamis?). It would have been possible to make rigid laws of nature without those things and others like them.