Questions regarding mass tower shield use and AoEs

[Sir Cirdan]

I'm making NPCs to inhabit a campaign I'm working on, and the standard soldiers are level 3 Fighter (Phalanx Specialist) With Longspears and Tower Shields. I'm planning on giving them the Shake it Off and Shield Wall feats to make them more resilient.

My concept for the army is that the front rank of soldiers use their tower shields for total cover while the second rank attack, meanwhile archers shoot over their heads and cavalry hit the stalled opposing army in the flank.

My question is this: would it be justifiable to give the phalanx, being a virtual wall of tower shields, either a bonus to reflex saves, evasion, or some other boon vs. blast spells like fireball?

Apart from a battle herald or feats like iron will to boost saves or dedicated counter-spellers, are there any other ways to provide mass defense against AoE spells?

[Avoron]

It provides total cover against attacks that pass through a square, and total cover blocks burst spells. Fireballs are spreads, so they can turn corners around total cover, but a solid wall of total cover from tower shields would stop them. Remember, spells like Fireball are "area" spells, not "targeted" spells.

The question is whether it means "attack," as in "if the invisible creature makes an attack their invisibility ends" or "attack" as in "when you make an attack, you roll an attack roll."

The feat Lastwall Phalanx is great for this sort of thing if it's a good army fighting evil opponents. +8 to saves and AC for everyone, although only +5 for those in the front lines.