As the title indicates, I don’t believe that Subaru can have both his name and memories eaten like Rem or the three Lye had eaten in Ep. 66 of Re:Zero, and Subaru potentially not being able to experience this doesn’t disprove my previous speculation about him not having immunities to Authorities.
Given Melakuera likely didn’t exist at the start of the time if Re:Zero’s fantasy world had ever been molten as lesser spirits take time to become Great Spirits, his words indicated that the world is constantly getting destroyed, and given Melakuera has retained his memories, it’s likely not an infinite loop as at least one entity is being re-summoned into the next iteration of the world with his memories, and that’s how I formed this theory.
In the distant past the final boss could very well have used his/her Authority to bias the story path of the world after the handsome, conceited, and overpowered hero of that era chose his lover over the world, and since then all iterations of the Hero of the story had to fit that mold of handsome, conceited, and overpowered until Flügel, Satella, and Echidna interrupted the story path of the world being destroyed for that iteration of the world/story to make artificial Heroes of the story in Al and Subaru. That would be why Flugel was such a bastard ’cause the final boss’s Authority forced him into that mold I mentioned, assuming my theory is sound.
I don’t believe Subaru is fully Flügel but moreso half of Flügel in the past given Naoko in Subaru’s first Sanctuary trial said that all Subaru needs to do is become half as cool as his dad, which is a strange thing to say to your son you know has an inferiority complexity centered around his dad, especially since he’s her husband, and thus, Naoko’s remark could have been foreshadowing of the situation from 400 years ago given Kenichi means “wise man”, Subaru called Flügel a wise man who lived centuries ago in Episode 16, and Shaula called her master, Flügel the Wise Man in Episode 70.
While Flügel was the Hero of the story, his soul may have been indivisible since the story required for the Hero to make it to the end and repeat the cycle since dying due to soul eradication wouldn’t be permitted, meaning he couldn’t split Subaru from himself then, but after returning to Earth and losing his Hero designation, he should freely be able to do that using whatever tool Echidna used to cut her soul off as part of her immortality experiment since he wouldn’t have that privilege he previously had as he’d lost his Hero designation.
Thus, Subaru likely cannot have both his name and memories eaten since it’s basically akin to your soul being eaten with your existence erased from the world, and as the current Hero of the story, his soul should be indivisible, meaning Subaru can only have either his name or memories eaten, not both, due to his unique privilege as the Hero of the story, not some innate immunity to the Authority of Gluttony.