1. Is it morals and good justice for a soul to be able to sin for a finite time and then have to suffer torture for infinity?
yes if it was warned so.
you kill a guy in two seconds and end up in jail for the rest of your life.
there's more to sin/punishment equality than duration.
if a sin is deemed of infinite evil, it is balanced by infinite punishment.
no contradiction or unfairness.
2. Is it good morals and justice for small or mediocre sinners to have to bear the same sentence as Hitler, Stalin and other genocidal maniacs?
i can slap you once per second for eternity, or i can slap you ten times per second till eternity.
not all infinities are equal, it's math.
3. Is it good morals and justice to continue to torture a soul in hell if no change in attitude or actions are to result?
yes.
jail for life, what good is expected if it's for life?
4. Is it good morals and justice to keep a soul alive in hell instead of killing it for mercies sake?
death would erase previous deserved punishment.
but the real reason why this thread is more or less useless[from a point of practicality], is that whether god is good or evil doesn't matter.
whether he exists or not does.
with infinite power you shape morality, both in people's minds and through their actions.