distinguo Randomness vs Disorder.
As all computer programmers know, randomness is a fallacy, there can't be anything random or God is not God. The Catholic Church teaches that the entire universe is held in the thought of God and if He stopped thinking of us, we would simply cease to be.
This is how Church documents appear to interpret what St. Paul wrote to the Ephesians
The Father’s Plan of Salvation. Blessed be the God and Father of our Lord Jesus Christ, who has blessed us in Christ with every spiritual blessing in the heavens, as he chose us in him, before the foundation of the world, to be holy and without blemish before him. In love he destined us for adoption to himself through Jesus Christ, in accord with the favor of his will,
Eph 1:3-5 NABRE
but it's not just us that He thought of, the universe, which was created good, was formed out of the void, not out of a preexisting disorder as in the pagan mythologies (see Bishop Barron's intro to the Word on Fire Pentateuch for this line of reasoning).
Bishop Barron goes on to mention in regard to the evil that crept into the world shortly after creation that the two "names of the dark powers" were ho diablos and ho Satanas. Diablos, I had no idea, meant "scatterer".
So when Jesus says that none of His disciples would be lost, He likely meant that they would not truly be scattered, but be One church; A mystical unscatterable body.
So the way the Church reconciles the divine plan is that it is a thing one seeks and only asymptotically "attains" in this life by living a life of virtue loving God and doing good works. Not being scattered, but being true to the True Faith that comes to use from Jesus via His Church.
Seemingly random evil events (cancer and tornadoes), you may attribute to the "passive will of God" direct divine intervention (miraculous cures and God speaking in a whirlwind) is called the "active will of God". Beyond that, it is a mystery and to know any more would truly sap the adventure, if not the joy, out of life.
A small child, or anyone without full use of reason, wouldn't be responsible for their actions or at least not fully responsible in the way someone with all their faculties would be. Mortal sin, at least, requires three things (CCC 1857):
- grave matter
- full knowledge
- deliberate consent
if grave matter is a given, full knowledge and deliberate consent are likely not