Answer: A (visionary) and F (extraordinary)

Blank (i): the "though" contrast
The key structure is "the treatises, though ______, hardly account for her prestige." The word though sets up a concession: the treatises have some quality that would seem to explain her prestige, yet they don't fully explain it. So the blank needs something positive, impressive enough that you'd expect it to justify a great reputation.

Visionary fits: the early work was brilliant and ahead of its time, but it still isn't enough to explain her current standing.
Derivative and pedestrian are both negative. If the treatises were unoriginal or mediocre, it would be no surprise that they fail to explain her prestige, so "though" would have no contrast to mark. You'd expect "because" or no connector at all.


Blank (ii): the "all the more ... given" logic
"All the more ______ given X" means X intensifies the quality in the blank. Here X is the persistent charge that her later work was methodologically sloppy.

Put it together. Her early work doesn't fully explain her eminence, and her later work has been repeatedly attacked. So where does the prestige come from? Her high standing is surprising, and the accusations make it even more surprising.

Extraordinary captures that sense of the remarkable.
Inevitable is the opposite of what the logic supports. Criticism makes her eminence less expected, not more.
Regrettable is the trap. It tempts you to read "sloppiness" as proof that she doesn't deserve her prestige. But the sentence only reports accusations; the author never judges whether her reputation is deserved. The sentence's logic is about how surprising her eminence is, not whether it's deserved. "Regrettable" would bring in a disapproving attitude the author never expresses.