Q 1)
If I have 3 Suicide Squad members... and all three of them are adjacent to a pog when the pog dies (or pushes to death), will it activate the Suicide Squad TA for all three of them? Do each of them take separate healing rolls or just one roll per dying person?

Q 2)
Say the 3 Suicide Squad are all at full and the pog were all hit by one Energy Explosion attack, will the damage resolve before the SS healing takes place? (therefore healing them after the attack and healing resolves) or will the damage occur after a non-effective healing (because they are already at full).

They would all get healed.
The EE attack resolves first (and at the same time), then the SSquad kicks in. They would take damage from the splash before the SSquad ability kicks in, provided the attack roll was high enough to hit them all. But that's kind of good, because you could roll high on your healing roll for some of them.