Hi Rohan,
I hope our priest friends find some time to visit us, but in case they get busy with their parishes, I found some info that may be helpful.
Here is what the
Baltimore Catechism has to say about the Last Things.
Here is the same thing in the
Second Edition English Translation of the Catechism of the Catholic Church.
What happens at the Last Judgement if we have already been judged before?(Any changes possible

) . Or is the Last Judgement applicable for only those alive at the time of the Last Judgement
If I read the Catechism correctly, the Last Judgment occurs for
all of us, both living and dead at the end of time. Christ comes again in glory. The resurrection of all the dead (just and unjust) occurs and then the Last Judgment. The Last Judgment seems to be a public judgment for all creation, as opposed to our particular judgment immediately after death.
I think the Last Judgment is for everyone, not just those alive at the time. It's different from our Particular Judgment in that we are judged publicly and after the resurrection of our bodies. At this time the just will be united with their glorified bodies and the damned will be sent to suffer eternal torment of the flesh and spirit. At least that's how I read it. Maybe someone else has a better handle on this.