Is a tiny creature with the feat Blades Above And Below able to flank?

I have an idea for a Fighter Eldritch Guardian (F-EG) archetype and, for fluff, I want to have an Azata Lyrakien (a tiny outsider) as a familiar (by the improve familiar feat).

At level 2, the F-EG gains the ability to share combat feats with his familiar due to Share Training.

The feat Blades Above And Below (combat and teamwork feat) allows to flank an enemy as long as you are in melee and threaten it no matter their position. But tiny creatures can’t flank. Now, as far as I know, if the tiny familiar is in the enemy’s square, it threatens it. The rules does not say that the creature has to have the ability to flank the creature, just that it has to threaten it to flank it. Am I missing something or is this an opportunity for my familiar?

Share Training: … it can use any combat feat possessed by the eldritch guardian…

Blades Above And Below: When you and your ally who also has this feat threaten the same enemy, you’re both considered to be flanking that enemy, regardless of your actual positioning.

I’m only interested in PF Society legal related answers.