FFIV is obtuse at times and this is one of them.
Before I started modding FFIV I always thought the 0x5 and all of that actually meant that the defense stat itself was being multiplied, but it means something Completely different, compared to how Attack Multipliers are calculated.
0x means the amount of times that your evasion will be taken into account to evade an attack. It's been a while so this might be wrong, Every 8 Agility will increase your Defense multiplier by 1 from there. This is how they balanced it so Edge would be an evasive fellow, while making sure the tanks (Cecil/Kain) have some actual ability to shrug off *some* damage. This is why Agility is king in FFIV, it increases your Attack/Defense/Speed/Evasion, all from one stat. You will notice in FFIV even Tellah starts with 8 Agility, hence he has one multiplier. However Rydia and Porom do not have enough Agility to reach even 1 defense multiplier and it looks the same with Firion there (great transfer of his portrait by the way, to the hack creator!)
For Magic Defense Multiplier is less straight forward. Tellah starts with x1, which implies that you need 16/Wisdom&Will to have a Magic Defense Multiplier, but its not so simple. it has to be 32 of either or both stats. So say if you have 16 Wisdom+Will you will have x1. If you have 48 Wisdom and 32 Will, you will have x2, because you haven't reached the new threshold of 96 to reach x3 Magic Evasion multipliers.