Nonetheless, regardless of the 'to hit' roll - the primary fortune mechanic of combat - the target receives the positive fortune - damage is inflicted.
No one is disputing this.
The outcome, regardless of fictional positioning, is therefore either 'success' or 'more success'. The fortune is always positive, the only thing that varies is degree of success.
(D&D is a bit unusual in that it doesn't normally tie degree of success to the fortune mechanic directly, and instead relies on a second 'damage' die. This sort of 'do you succeed', 'if so, by how much", logic occurs in several areas of the rules.)
This assumes that there is no cost and no investment from the player and the character. It ignores the character as a whole, and does not recognize that the ability is a design choice that has been made, eschewing other abilities that are at least comparable. The minimal damage guarantee comes at the expense of other, arguably cooler options that are available to every fighter, paladin, and ranger.
And the degree of minimal success is the result of the character's strength score, which also represents character investment (and is dependent in some campaigns on the luck of a die roll).
I answer these questions completely differently:
Success regardless of fictional positioning: Yes.
Mechanic is absolute: See above.
Involves a no fortune roll: No. But outcome of fortune roll determines only degree of success. Therefore, fortune roll involves automatic success.
Tells you what must happen: Yes. Regardless of outcome of fortune role, the result of a proposed attack is always that the target receives some minimally impactful blow. This violates are intuitive understanding that an attack is a risky proposition.
...so I still stick with no to all four.
We're not going to convince each other on this, clearly. To say "the target receives some minimally impactful blow" is a fiction you are imposing on the situation; it is not in the rules. To say "the target's pool of hit points, an abstract number that represents the ability to persist in physical and magical combat, are marginally reduced" is better (but could still be tightened, obviously). Nothing tells you what must happen. An attack remains a risky proposition, and my intuition is in no way violated.