I'm glad I asked! My first assumption would have been to go with canon character because playing the game so long does bias one's view a bit, after all.

And that's good to know on the other point too! Thankfully there's canon precedent for such a situation even if it's a year beyond what's currently appable from the English version so I can work with that.

That does make me think of a follow-up question though. I'm guessing you're already at least passing familiar from existing Fate/ cast with how Servants need a supply of magic and such to stay manifested, which is usually provided by their contracted Master. In the case of FGO's protagonist, that energy is actually provided by Chaldea's systems and not her personally. (Which also is part of how she can contract with multiple servants simultaneously.) Given that the simplest explanation for being unable to summon is being cut off from Chaldea, would it still be safe to assume there's either some latent connection and/or that local energies would fill in as a substitute?

Specifically I ask so I can know whether forming temporary contracts with Master-less Servants from Fate/ incarnations other than FGO would even be possible in the first place, should it ever happen to come up ICly.