That's incorrect, the devouring tentacle comes from the 3rd. MC recounts that he used it on him when he's telling his infection story to Alice, Michael and Deryl. It also makes sense because the 3rd had the MC in his grasp but still couldn't read his memories without directly using his tentacle on his brain. So Ella got the devouring tentacle from her papa. She just doesn't have the memory function of it like him, as far as we know. To add more to it, the MC points out the difference between his devouring tentacle and the 4th's method when she's the parent. Meanwhile, MC with 3rd said he does the same as him, when it comes to acquiring a lot of memories.
I'm not talking about the tentacle per se. I'm talking about how the matter is absorbed. MC's way of sucking the matter is distinctively different than Ella's who creates tiny mouths to chomp on flesh.
If that's the 3rd's ability, then wouldn't it make sense that Ella would use the same mechanism? Additionally, why even teach MC just to transform corpses to pebbles and not.. eat them? After all, eating meat increases energy reserves and consumption generally makes superhumans more powerful. Level 3 MC naturally does this with his tail. He compresses the Security Chief and then consumes him. Additionally Ella is a high corruption character, but she prefers killing without consuming. MC, played as high corruption, has a natural instict for it.
Edit: To clarify,
The paralysis idea is a different approach to a common goal. Both Apostles want to immobilize MC, so there is an obvious difference here that can be observed directly in the scene. So I'm happy with just that.
In the case of the matter absorption, it's something that only the Fourth has reason to do during the infection scene. The Third does not at any point during the infection scene, absorbs matter. He uses the tentacle to probe and prod, but this isn't about memories, it's about consumption/absorption. Even if the Third has a tentacle that looks like MC's , the functionality is different. So we need more info, and since Ella is confirmed to not have the memory trait, by observing the differences between her and MC, we may be able to find the originator of the ability.
The paralysis part is also not quite right. That's likely a natural ability monsters have. The 4th and 3rd did the same to the Minyaks. Hex does the same to Level 2 MC before his fight with Nico. Seeing as S-Rank monsters and above used it, it likely requires a vast power gap to do or for you to be a S-Rank monster. Possibly even a pure lineage too. Especially since the A-Rank monsters we saw during the Battle of Diamonds couldn't do it to Level 2 Laurie and the others. Neither did the Asura to MC, even though it had more than 10 times his power.
I don't think what you describe is an ability. It's the power differential which overwhelms the "monster sense", similar to a fight or flight response. It happens in various points in the game.
Deadend3 with Memory.
In the car with fairy's cannister.
With Hex during the SIN announcement scene.
However this doesn't affect humans in any shape or form so it shouldn't affect human MC.
Michael and Alice can't feel the fairy like MC can.
The audience flees when Cole starts talking, but MC feels extremely heavy.
MC during deadend3 understands what a fool he was, because he couldn't sense the Apostle during his infection.
Lastly, I wonder why WW would have the two Apostles using different methods of immobilizing MC. Sounds a bit odd to me.