Fate/Extra Western Release! Also: Sequel Planned!

With science as it is at the end, the real protag will be saved if Rin finds him/her, just with the loss of their memories. It is clearly stated at the end that, considering how she/he was the whole war, they will do just fine in getting back on their feet despite memory loss, and with Rin at their side, they'll have someone to help them (for those Rin romantics, it's obvious that they'll be together in the end, what with Rin being so devoted and the protagonist seeing her in that light...should you have seen her in that light).

The data protagonist, will not be transferred into the real protagonist. However, they were based off the real protagonist's personality, so the real protagonist will act and think exactly like them...just minus the battle experience (care for life and friends, care for people's individual dreams, the uneasiness about killing, etc.). Every emotion the data protagonist felt is one the real one can and likely will feel. So, in the end, the data protagonist dies with their closest friend/lover and the real protagonist lives on with their eventual closest friend/lover.

Things to remember:
1. When a character pledges to find another at the end of a story, it's meant for you to assume that they will post-narrative. It's just a simple trick writers use to keep their readers thinking about the story after it's finished.
2. Rin is part of an insurgency, so obviously she'll have contacts to soldiers, doctors, and the like who can help the protagonist (this being 20 years later, it's only reasonable Twice's research was expounded upon by other doctors and possibly perfected).
3. The disease affects memories, not the body, and the body is in cryogenic stasis so the protagonist will be fine muscle-wise. ...Though it will be like waking up from a long~ sleep with the worst hang-over you ever had and enough joint pain to make them wish they were in a coma.
4. A persona who loses their memories does not lose their personality. They CAN lose their personality if they allow the reasonable desire to remember their past to overtake them, and if they follow the wrong crowd. With Rin at their side...well... It's hard to go screwy with a girl like her as your friend/lover.

Rome was on good relations with Britain and they in fact got along with Nero and liked the way she treated her citizens, for the most part, Nero actually put her people before politics

Who did you choose to save? Rin or Rani? I'm assuming the story is the same no matter which Servant you picked. And the story will be a bit different too depending on who you saved.. I think.

I picked Rin. Going for Rani in my next play through.

I went for Rin of course I dont like Rani's character all that much and well Rin is Rin so it was an easy choice. The dificult part was having to use 2 command seals