Must the layers of the Prismatic Wall spell be destroyed in order?

Must the layers of the Prismatic Wall spell be destroyed in order?

You’d think this is answered read-as-written on page 269 of the 5e PHB:

The wall can be destroyed, also one layer at a time, in order from red to violet, by means specific to each layer.

However, I know I’ve seen multiple people around the internet talk about strategies of intentionally destroying certain layers of their own wall like the red, orange, or indigo layers, and holing up inside the wall and shooting or casting spells through the wall without those layers blocking them.

It also begs a question like “If a fireball hits the wall as part of battle and does 25 damage, does it destroy the blue layer individually?”

I just want some validation that you really do have to hack each layer down from red to violet as opposed to losing middle layers intentionally or unintentionally as part of the overall battle.

If you pass through the order of colors in Prismatic Wall one way, do you reverse the order of colors passing through the other way?

I set up a Prismatic Wall and a non-protected creature passes through it, say from left to right. On page 269 of the 5e Player’s Handbook, the spell reads:

“When a creature attempts to reach into or pass through the wall, it does so one layer at a time through all the wall’s layers. As it passes or reaches through each layer, the creature must make a Dexterity saving throw or be affected by that layer’s properties as described below.”

The layers are listed from Red to Violet, so the enemy passed through my wall in that order and made it through. They are now on the right side, and I have contrived a way to push them back through the wall to the left side. Do I reverse the order they encounter the layers and go Violet to Red, or do I always go Red to Violet whenever anything passes through the wall?

In other words, does a Prismatic Wall have a “sidedness” to it, and, if so, when is that sidedness established?

Can an Area of Effect spell cast outside a Prismatic Wall extend inside it?

The Indigo layer of a Prismatic Wall states :

While this layer is in place, spells can’t be cast through the wall

By comparison, a Globe of Invulnerability states :

Any spell of 5th level or lower cast from outside the barrier can’t affect creatures or objects within it, even if the spell is cast using a higher level spell slot. Such a spell can target creatures and objects within the barrier, but the spell has no effect on them. Similarly, the area within the barrier is excluded from the areas affected by such spells.

It is quite clear that, say, a Fireball cast outside of a Globe of Invulnerability can’t extend inside it… But Prismatic Wall seems to lack this clause. So, would a Fireball, or other area of effect spell, cast on a point on one side of a Prismatic Wall extend through the other side of said wall ?

Dwarven Resilience vs. prismatic spray

The prismatic spray spell can do different damage types (and status effects) depending on a d8 roll for the target. Now what happens if the target is a dwarf and thus has dwarven resilience and the attacker rolls an 8 initially then one of the two rerolls is a 4 which means poison damage? Since dwarven resilience provides advantage vs poison attacks (not just advantage against being poisoned like protection from poison) the dwarf should get advantage on the save – even though the other effect might not be poison related. Is that correct?

How many damage rolls would you make for prismatic spray?

Unlike most spells, prismatic spray (and prismatic wall) can do a number of different damage types depending on dice rolls. But how many rolls would you actually make? Just 10d6 one time and apply the same damage to all damage rays? Or 10d6 per ray (only the ones that actually hit)?

If the latter, what about metamagic like empowered spell or the cutting words ability to reduce damage?