So, question: If she could get it, do you guys think Mathilde's combat style would benefit from her training with wood elf war-dancers? Because not only are their leaders IIRC sometimes wielders of Ulgu, war dancers worship a god of trickery like Mathilde, fight without heavy armor, and they have an extremely mobile, hard to hit combat style that uses two-handed weapons. If the Armor of Von Taurnus ends up not winning the vote, developing her personal combat style to to compensate might still improve her survivability.
Similarly, since the Elfcation is coming up, she might have an opportunity to get some pointers from a loremaster or swordmaster. They are known for their ability to parry projectiles, after all, and loremasters are familiar with incorporating magic into martial combat.
And unlike the magical techniques of their order, I suspect that their sword techniques are probably not as closely guarded secrets as their magic techniques would be.