"Ioudaioi Ekatontamachoi", how they would look like.

[MeinPanzer]

On the subject of armor/non armor: The vast majority of the thureos carrying troops depicted in both Sidon finds and Palestrina ones are unarmored.
In the case of "Ekatontamachoi", however, I don't believe that this would have been the case. Seeing that these men (or their king) went the extra mile and had their wooden thureoi covered with bronze, they would have at least spend some money first getting some sort of armor.

Other armies of the area and time did also have that distinction.

Hastati/Principes
Thureophoroi/Thorakitai.

The same one would exist on the "Army of the Sons of Light" I believe.

First slingers, then 3 lines of unarmored javelineers who would hurl their javelins at the enemy and then...

The final line, of older "men of the rule", comprises two ranks/lines of infantrymen, the first with shield and spear, the second with shield and sword.11 The description of the infantryman given above most probably applies to these men then, either the first or possibly both ranks. These men are to fight in close order (4Q491 - 13.7), and deliver the final blow to the enemy battle line. Once it has been routed, the trumpets sound the signal for all 7 ranks/lines to advance together to inflict as great a slaughter as possible

http://www.ne.jp/asahi/luke/ueda-sarson ... Light.html

While these "men of the rule" are not mentioned to be wearing armor, I think that at least some if not most of them are. It doesn't make sense for a ruler to not arm and equip his men in the best possible way, since if anyone can win the battle, they can. They should live to fight another day, therefore they would need to have some sort of wearable armor.

In the hastati/principes order of battle weren't the principes the veterans, old and grizzled, and almost all of them clad in mail or other armor?

I think it's probable that they did wear armour, but we have to be careful that we don't let our conceptions of what makes a unit most effective colour our view of the past- most heavily armoured was not always equated with most effective in combat. Perhaps they thought that with an up-armoured shield, it wasn't necessary for them to wear body armour, allowing them to be more agile in combat, or some other reason. Compare the fact that we sometimes find depictions of soldiers wearing body armour, but no helmets; to most nowadays, a helmet would probably seem higher priority than a cuirass, but evidently that wasn't always the case in ancient times.