What do the Catholic Church consider constitutes intrinsically impossible things? We all know that by his omnipotence, God can do anything and everything "possible".

Q1. If so, what things are considered by the Church to be "impossible" for God to do?

Q2. Is it correct to say that an event is not an impossible event as long as the event has "some possibility" to occur in future (even if it be a very, very slight possibility)?

Thank you,
The Catechism contains a definitive statement on this.

Nothing is impossible with God, who disposes his works according to his will.
[CCC 269]

It references a number of biblical texts to support that statement:

It was I who made the earth, and man and beast on the face of the earth, by my great power, with my outstretched arm; and I can give them to whomever I think fit. — Jer 27:5
Ah, Lord GOD, you have made heaven and earth by your great might, with your outstretched arm; nothing is impossible to you. — Jer 32:17
[And behold, Elizabeth, your relative, has also conceived a son in her old age, and this is the sixth month for her who was called barren;] for nothing will be impossible for God.
— Lk 1:37

It goes on:

God's almighty power is in no way arbitrary: &quot;In God, power, essence, will, intellect, wisdom, and justice are all identical. Nothing therefore can be in God's power which could not be in his just will or his wise intellect.&quot;
[CCC 271] quoting St. Thomas Aquinas, Summa Theologica I, 25, 5, ad I.

This explains things which appear to be impossible: they are impossible because God does not include them in his wisdom or justice. Anything which is impossible is impossible because it does not obey the natural laws of the universe, which is ordered according to God's will. However, he could will impossible things to happen if they are not contrary to his nature and are necessary for revelation and salvation. Thus he can allow a chariot to ascend to heaven; or water to become fine wine; or a Virgin birth to happen; or a dead body to be resurrected, speak and walk.