Analysis:Does Remember 11 Have a Happy Ending

Yukidoh and Enomoto in the End
When the Final Level is achieved, [ORE] leaves the world and the body of Blondie becomes an empty vessel. At the same time, the body of Sunglasses has been decomposing ever since it was killed by the fetus α on the 4th day. So what happens to the real Yukidoh and Enomoto?

A very similar scenario happens with Hotori and Inubushi: Hotori's body died on the mountain while the Shadow within Inubushi goes to the Final Level, leaving Inubushi's body empty.

Unfortunately there isn't much information to tackle this issue, so we're left to speculate.

Scenario 1: Death
It's possible that Self has completely overwritten the old personalities, so Yukidoh Satoru and Yukidoh Sayaka are lost completely from the world. The body of Blondie and Inubushi experience brain death since there is no personality within them. Their personalities are lost forever.

Scenario 2: Ascension
If Self merely ejected their personalities, both Satoru and Sayaka's personalities would be free-floating. The bodies of Blondie and Inubushi would still be physically dead, but Satoru and Sayaka remain alive in spirit. In that case, they may have transcended their physical bodies and become immortal, perhaps even becoming a part of Self.

Scenario 3: Return
Finally, if Self suppressed their personalities, then the last personality within a body would return to it. That means Satoru's mind returns to Blondie's body, and Sayaka returns to Inubushi's body.

Enomoto and Hotori
The fate of Enomoto and Hotori, on the other hand, seems more certain. Their personalities died while occupying a physical body, so it's likely that they are completely gone from the world.

However, the influence of Self may have effected their fate. It's possible that a person's true personality exists within their brain. Since the player no longer intervenes in the world, the personality of Enomoto which exists within his brain begins to express itself. If Satoru does not return to his body as in Scenario 1 and 2, it means that Enomoto returns to his original body.

On the other hand, if Enomoto's personality returns in Scenario 3, both Enomoto and Yukidoh would compete for Blondie's body. That may result in Blondie getting Dissociative Identity Disorder with both personalities remaining alive, but sharing one body.

So could Hotori survive in the same way within Inubushi's body? There's no way to know for sure, but as Kokoro says:

"If there isn’t a logical explanation, wouldn’t you rather believe the most romantic option...?"

So it’s a happy ending?
If you take the most optimistic approach so far:

The real Hotori's body froze to death on the cold winter ground, Inubushi seems to be ready to drop a baby into the sea, Enomoto was stabbed repeatedly, as well as Yukidoh, The consciousness of Hotori and Yukidoh are preserved as split personalities within Inubushi and Enomoto's bodies, respectively.

Not a single consciousness will have died. Only the player is gone.

If you accept this, does that make Remember 11's story a happy ending?

Blondie and Sayaka have multiple personalities. Will they share their bodies equally with the other consciousnesses...?

Will it be possible for the consciousness of Satoru (Sunglasses) to reunite with Mayuzumi? Or would they be deceiving themselves, essentially going out as different people? Wouldn't it be difficult if a personality changes halfway through their interactions?

And more crucially, what about the relationship between the Yukidoh siblings? Even if he's her brother, he's in another body that keeps switching personalities!

What kind of strange world have they created...?

Final Word
Self is capable of changing the world as it desires. It subjugates human will, bends time and space and creates personalities from nothingness. Its influence even spills out subconsciously. If you believe Self is capable of anything, then the world that exists beyond the epilogue is entirely in its hands.

So ask yourself, what kind of ending do you desire? One where Satoru, Sayaka, Enomoto and Hotori are dead? One where they all live as split personalities? Something in between?

Did the YUKIDOH plan succeed? Was it a failure? Where is SELF? Is it still imprisoned within the inescapable maze of memory? Or has it escaped the Infinity Loop?

The omnipotent, omnipresent nothingness that permeates the world: what have you decided?