Can an Elder Oblex be subject to an AoE more than once?

Question

The Elder Oblex has the Sulfurous Impersonation feature which lets it create an impersonation of a creature in another space. The feature goes on to state:

For all practical purposes, the simulacrum is the oblex, meaning the oblex occupies its space the simulacrum's space simultaneously.

In the likely event that the Oblex has multiple simulacrums on a battlefield, what happens if 2 or more of them are subjected to an area of effect spell like fireball? Does the answer change for a wall spell like Blade Barrier?

Answer 1

No.

As you have observed, the Sulfurous Impersonation feature says:

For all practical purposes, the simulacrum is the oblex, meaning the oblex occupies its space and the simulacrum’s space simultaneously.

Since a spell like fireball only damage creatures once, and we treat the Oblex and its simulacrum as one creature, it is only damaged once. Blade barrier functions the same way. It can only damage a creature once per turn.

Answer 2

The Elder Oblex suffers the effect once

All AoE spells AFAIK have a phrase similar to “Each creature in ...” (from Fireball). The EO is a creature in the AoE.