You might notice that those who cite "Simply put, a unit that outranks its enemy is considered steadfast" like a mantra in their defence, take care to cite it without any context. This leads to interpretations like option 1, which I think virtually all will agree is simply ludicrous. The supporters of 3a, as Nexus indicates above, take this to mean "Steadfast is a temporary status that applies to a unit that outranks all the enemy units it is in combat with." But of course, that is also not what the statement actually says.
Obviously, this statement (like any, really) must be read in context.
So what is the context? Please take your BRB and go to page 54, where the rules concerning steadfast are explained.
First the general context: allow me to draw your attention on the heading of the chapter: 3. LOSER TAKES BREAK TEST. On page 54 and 55, the rules and regulations concerning break tests are explained. I think, we can safely conclude from this that Steadfast is a special rule, when taking a break test. One will find no reference to steadfast in the BRB except as part of taking a break test.
Let us go now to the subdivision: Steadfast
Immediately following Steadfast you will find:
If a defeated unit has more ranks than its enemy, it takes its Break test on its unmodified leadership.
The bold lettering is from the BRB, and indicates that this is a summary of the rule, while the remaining paragraphs will explain the rule in more detail. Note that it says: a defeated unit, a reference that you will always find in connection with steadfast, as I have pointed out in previous posts.
The next paragraph is the "fluff" paragraph, which is sufficiently vague that it could be read either way.
Then we have the notorious:
"Simply put, a unit that outranks its enemy is considered steadfast".
Except that it does not stand on its own: the text further explains how the ranks are counted. This is done: "as with calculating ranks of combat resolution", which I think we will all agree happens AFTER combat. So, the number of ranks which actually determine whether a unit is steadfast or not are calculated AFTER combat, not before. Therefore, a unit cannot be steadfast before combat resolution.
The next 2 paragraphs do not add anything either way.
But the example that follows gives again the sequence: combat, combat resolution, then determining ranks to see whether the unit is steadfast or not.
So, you simply have to ask yourself: does the text that explains steadfast read as a whole support
1. If a defeated unit has more ranks than its enemy, it takes its Break test on its unmodified leadership
- which is actually found written in the BRB.
2. "Steadfast is a temporary status that applies to a unit that outranks all the enemy units it is in combat with."
- which (or something similar) one cannot find written anywhere in the BRB.