Multi-classing and prerequisites

Question

The character begins as a 10th level human fighter and then received an extra benefit at the adventure's ending; he is discovered to be an Elan (not a human, GM's alchemy) gaining psionic capacities. For the next two levels, he advanced as an Aegis becoming a multi-class fighter 10/aegis 2.

In the manual is:

Greater Weapon Specialization (Combat)

Choose one type of weapon (including unarmed strike or grapple) for which you possess the Weapon Specialization feat. Your attacks with the chosen weapon are more devastating than normal.

Prerequisites: Proficiency with selected weapon, Greater Weapon Focus with selected weapon, Weapon Focus with selected weapon, Weapon Specialization with selected weapon, 12th-level fighter.

Can this character take "Greater Weapon Specialization"?

Answer 1

No, a “12th-level fighter” is someone who has 12 levels in the fighter class, not merely someone with 12 levels total and some levels in fighter. You do not qualify for Greater Weapon Specialization.

To confirm this, consider how the books write the classes of multiclassing characters: if this character appeared in a book, they’d be a “10th-level fighter/2nd-level aegis.” A 10th-level fighter is not a 12th-level fighter.

Ultimately, that’s ok—Greater Weapon Specialization is a terrible feat. All of the fighter-only feats are. You can do much better looking at the feats that don’t require fighter levels.

Answer 2

No.

Greater Weapon Specialization says:

Choose one type of weapon (including unarmed strike or grapple) for which you possess the Weapon Specialization feat. Your attacks with the chosen weapon are more devastating than normal.

Prerequisites: Proficiency with selected weapon, Greater Weapon Focus with selected weapon, Weapon Focus with selected weapon, Weapon Specialization with selected weapon, 12th-level fighter.

Benefit: You gain a +2 bonus on all damage rolls you make using the selected weapon. This bonus to damage stacks with other damage roll bonuses, including any you gain from Weapon Specialization.

Special: You can gain Greater Weapon Specialization multiple times. Its effects do not stack. Each time you take the feat, it applies to a new type of weapon.

They only have 10 levels of fighter, not 12. Aegis does not stack with your fighter levels for meeting prerequisites either, so it doesn't help in this case.