How to check how much HP Nemesis has?

[Evil_Baka]

Oh, that can be that! Since Regurgitators have the same poison resistance reduction aura that the Necromancer’s Blight Beast has, they reduce Nemesis’ resistance.
Does that also mean that there is no way to increase the resistance of Nemesis via pet resistances, only via buffs?

This and the comment above it are correct:

Will summons like mortar trap benefit from IEE's conversion?

Imagine that a player scaling pet is an extension of the player. When it attacks, it’s as if the player cast the skill.

Which is why Living Shadow attack damage converted to health heals the player.

Likewise, while IEE benefits the player and thus by extension any player-scaling pets, the pets themselves do not double dip into the auras. The visual effect is just the nature of auras applying their visuals to all nearby allies.

However, Player-scaling pets have their own health/defenses, so increasing your Poison Resist to help the Deathstalker survive is purely placebo. Those kind of pets already have about 90% resistance to all damage. What can wreck them is resist reduction effects. Most other player-scaling pets (such as Mortar Trap, Wind Devils and Thermite Mines) are invincible and generate no threat in combat.