I don't see the problem. Part of the terms of the Peace of Lodi was that each signatory power would protect the other against threats from without. Wikipedia says:But there is a problem in proposing any date after the 1454 Peace of Lodi for the PMB – why is the King of Swords holding (ironically, IMO) the coat of arms of Venice on his shield and why is the Fortitude card likewise showing the symbol of Venice, arguably the lion of St. Mark (given the circumstances), prostrate before an impending blow from a conquering imperator? Neither would fit the hypothetical circumstances of the PMB issued to commemorate the peace between Milan and Venice. The King of Swords is especially a problem – why would Sforza be portrayed as Venice’s protector (i.e., the shield) when Colleoni held that position now (and Colleoni had been leaning in that direction for some time)?
So in a sense Sforza is the protector of Venice, and vice versa. Sforza was that once, in a different capacity, and now he is again. Anyway, he gave up being protector of Venice, in the sense of a condottiere, long before 1454.A principle of a balance of power in Northern Italy was established, one that excluded ambitions of smaller states: the republic of Genoa, the house of Savoy, the Gonzaga and the Este.
The Lion on the PMB Fortitude card is being attacked by the man; if the Lion were Venice, that would not be a very diplomatic message to send. In fact the lion was traditionally associated with the virtue of fortitude. It had been a lady with a lion in the CY. For the person to be with the lion represents their bravery, whether it is St. Mark taking a thorn out, Hercules or Samson killing it, or the lady doing whatever she is doing.
I think more is required than a word or concept simply occurring in a particular canto or group of cantos. These words occur in several cantos. It is a matter of the theme being emphasized in a particular group of cantos, more than in others.7 EXEMPLARY THEMES (key Paradiso canto in corresponding planetary sphere)
Empress (III.109f), Emperor (VI.1.27f), Love (VIII.2f), Chariot (XII.106f), Wheel of Fortune (XVI.82f), Judgement (XVIII.91f), Death (XXI:4f)
On that score, Empress, Emperor, and Love work well with Dante's canto-groups. Empress Constance is a major figure associated with the Moon, as is Emperor Justinian with the sphere of Mercury, and Cupid, i.e. Love, with Venus. On the other hand, Emperors are also mentioned in canto XX in connection with their want of justice; and the only time the word "empress" is used is at the end, I think referring to the crowned Virgin.
After that the Chariot of the Sun is a possibility. It's the only place where a chariot is mentioned that I can find. And the Sun is the planet most often associated with a chariot, viz. the Phaeton myth. The main theme of the canto is St. Dminic and St. Francis, the two wheels of the chariot, dispelling heresy, in other words bringing light to darkness. It could have been a theme of some hypothetical tarot card. And the golden coin on the CY card does associate the card to the Sun. A woman, Aurora, did ride the solar chariot at dawn. As I recall, she had an older male lover, who could be envisioned as stopping the horses so she could get off. It also, I still maintain, could be a Phaedrean Chariot with its ruly and unruly horses. That fits a Petrarchan interpretation of the card.
In the type A cities (Florence, Bologna), the Chariot card as it appeared later seems more connected with Mars and the triumphal warrior than anything else. Especially after a victory like that of Anghiari that would be the case.
In the circle of Mars, Dante features Death at least as much as Fortune, and much more than in the cantos you associate Death to. The circle of Saturn is that of contemplatives, not death. It is true that there is a brief mention of of death at the place you cite, that of Semele when she beheld Jupiter in all his splendor. But the point is not about death, it is about contemplation of the divine, which for mortal eyes must be tempered.
The circle of Jupiter is about justice, in relation to earthly judgment, more than the Last Judgment. The latter is only brought in as a model for earthly rulers (mentioning several emperors). Anyway, the early name for the card was the Angel. The Angels were in the ninth sphere, an appropriate place for the Angel card from a Dantean perspective (and cosmographic presentations generally).
After that, the type A World card does fit, and the PMB World, but not the CY card with the castles. I am at a loss to know how that card fits any Dantean theme, as opposed to Petrachan Fame.
And surely Death would be before the Last Judgment in the sequence. I could see Hope, Faith, and Charity coming after Death, as the keys to immortality, but not Judgment. (However these virtues figure into several cantos of the Paradiso, faith throughout, hope and charity especially in 2-3 and from 20 on.) Since the circle of Saturn is for contemplatives, an old man with an hour glass would be appropriate, reminding us of Death's approach, or with a lantern, as in the image of Saturn done during the 14th century and preserved in Milan with the Song of the Virtues and Vices.
You insist that there wasn't time between whenever it was in 1440 and October 1441 for a deck with different subjects from Milan. I don't see that at all. Many of the CY cards are unlike anything in the type A cards. If they can design different scenes, they can add a couple of subjects as well, especially if they have increased the number of suit cards. Filippo would have wanted his deck to be an improvement on anything Florence could muster. And Dante, unlike Petrarch, has no particular relationship to Milan. That Petrarch preferred Milan to Florence would have been a nice thing for Filippo to flaunt.
Also, it remains a very big assumption that there were no trionfi decks before 1440 and Anghiari. The diary entry uses the word "tronfi" as though it were a name already established for decks of a certain sort. Just because surviving documents first mention a certain date, that doesn't mean it didn't exist before that date. There are counter-examples from near that time and place (the first surviving mentions of eyeglasses, stating they existed 20 years earlier), and and a vast quantity of records has been lost over time: in Milan by 1450, in Bologna in 1506-7. In this situation, it would be a great coincidence if the first surviving mention was also the first ever example.