There are five book of the Bible that are considered as “Poetic Books“.- by form.
They cover three periods- Psalms of David and the last three of Solomon and Job the first Patriarch period.
These five poetical books are of human experience and are about individuals and considered Books of the heart. They are also divided into what might be called sub categories. They are called for sermons “Voices”
So you have in order of below

Job is the Voice of the Spirit or blessed through suffering (Not used often in Sermons especiall15th Century)
Psalms is the Voice of Heart or Prayers/Songs of Praise
Proverbs is the Voice of the Will (B) or Instruction by comparison
Ecclesiastes is the Voice of the Mind © or a search for the meaning of Life
Song of Songs is the Voice of the Body (A) Allegory of a marriage- God’s and Church’s Love,

The three books of Solomon (attributed to) are looked at as a Young persons Love (A)
a middle age man’s wisdom (B)and an old man’s sorrow (C )

These 5 books are overwhelmingly the examples in Sermons in the Late Medieval period and used in
Mass throughout the Liturgical year.
(As a teenager the Song of Songs would create high hilarity and sniggers because we were ignorant )
Aside from the Theological Virtues- the 4 Cardinal Virtues appear to be used in Sermons as examples of attributes to the Books- so Prudence or Wisdom to Solomon in Ecclesiastes -the Voice of the Mind, Shulimite or Nuns Like Saint Catherine to Psalms for example- but the persons and books were interchangeable.
The sermons were very Humanistic in ideas in the 15th Century.

Apart from ranting about Sodomy, Heretics etc there is one subject that warrants special mention in Sermons. That is that of Usury and a different Biblical example was invariably used.
It says in Isaiah 24:2-3, “And it shall be, as with the people, so with the priest; as with the servant, so with his master; as with the maid, so with her mistress; as with the buyer, so with the seller; as with the lender, so with the borrower; as with the taker of usury, so with the giver of usury to him. Examples were taken from Ezekiel, Exodus and Leviticus
and centred around The King of Tyre who was considered Satan. (a whole other subject which may have applied to Florence but not Milan and a viable reason why The Devil and Tower does not appear in Visconti Sforza cards )
So If we were to construct a Sermon or a hand of cards for that matter, you could look at the VS in sets.
Four Types : Papesse/Empress/Emperor/Pope or Books (Job was not used much as examples nor sung)
Four Virtues : Prudence: (Solomon :Hermit )/Justice/Fortitude/ Temperance
Four concepts: Union:Love/ Death/ Mercy/Reward
Four heavenly reflections : Star/Moon/Sun/World
Four Metaphors Fool/Magician/Chariot/WOF
all very Humanist in relating the Classics with Christian thought-and applying to the the world they lived in as man in charge of his own destiny and not some puppets of God and Church.
~Lorredan

Some questions:
I don't understand your rationale for excluding Devil and Tower in Milan but not in Florence. It seems to have something to do with Satan, but I don't get it. Also I don't understand why you talk about usury. What is the relevance? Are you thinking of the Hanged Man as a usuror?

Also, What cards are "Mercy" and "Reward"? Is "Mercy" the Judgment card? If so, what is "Reward" ? And what is the function of the word "union" in this row?

The Medici of Florence were Moneylenders/Bankers and a common theme of Sermons in places where Bankers lived
in Lombardy was the Sins of Usury. Interest was an unavoidable sin of Banking-Christians were not supposed to get interest on their loans and they had special ways of describing interest so it was disguised. The two cards that represent Usury are Satan and The Tower. Sforza as not a Money Lender. Usury did not apply to him. The enormous wealth that allowed the magnificence of Florence was the result of Interest or Usury and no matter how disguised- interest was a sin to a Christian.
Jewish Bankers were allowed because they could not commit the sin of Usury.

Union = Lovers card= Marriage = concept of Marriage in the usual sense and Mystical Marriage
Mercy= Hanged Man Card =punishment of debtors are forgiven= just as Purgatory is Heavens Gaol
Death= Is only Physical Death For your soul/spirit stands in the Communion of the Saints
Reward= is Resurrection. Only Christians will rise to be in Heaven
You are judged on how well you loved God in the only way possible- on how well you lived your life, how in balance was your heart, mind, body, and will.(an egyptian concept of the weighing of the soul)
~Lorredan