“Foundation” conveys the idea of “coming first”.
It denotes a thing that must be before other things can be.
While it is interesting to examine the sequencing of virtues, I think the important point is to examine how we can grow virtues in people.
Our world is a very computerized world now. Things happen so fast in computers that to us, they appear to happen at the same time.
But they don’t. There is a sequence.
I spent the summers of my youth on a dry land grain farm. I saw the organic process of growing things. I saw that sequence play out over months, not milliseconds.
You can’t harvest unless you plant first.
For us organics, humans, I think that courage must be present before the other virtues may blossom.
If we are to harvest virtue(s), I believe we must first plant courage.
If one wants to look at sequencing, which you make a reasonable case for, off hand, I’d suggest Temperance/Self-Control.
I’d do so on the grounds that the gifts of the Holy Spirit are traditionally sequenced Fear-Piety-Knowledge-Fortitude-Counsel-Understanding-Wisdom (the Fear of the Lord is the beginning of Wisdom), and that Fear is traditionally associated with the Cardinal Virtue of Temperance. Piety is associated with Justice.
One cannot begin to tackle difficult things well unless one has some self-control and some idea of what is just. Without these, one ends up looking like Sampson.