[Illidan]

Unless I missed something it looks like the official title is just Fate/stay night in both the english and japanese websites.

We can use a different name in the product field so it doesn't mess up with related albums, like "Fate/stay night (2014)", but I think we should keep the display title as it is, unless they change it in the future of course. Same as we did for Jojo.
Even if you change it, it will have the same name as the studio deen movie so people are gonna get confused anyway. If we really need to, then we can use something like "Fate/stay night: Unlimited Blade Works (TV)".

The HF movie is called "劇場版「Fate/stay night」Heaven's Feel" so it can be named "Fate/stay night: Heaven's Feel"