Shirou and Henrietta hook up at the end.From Louise's reaction in the epilogue it was one of the friends she shipped with him. That would mean either Siesta or Henrietta. Considering Shirou's reaction at both of them it's pretty obvious which one he chose.
Corollary: Henrietta's unborn child will be a girl by the name of ArthuriaSomeone to Remember Him By. It helps that Henrietta had been impressed by her image during the ball and naming children after famous people, including ancestors was common practice.
- And she would be THE Arthuria Pendragon. Because we had ample proof that the Root is a malevolent sentient entity with a twisted sense of humor.
- Wait, would that make Saber and Shirou... FATHER AND CHILD!? The Root is malevolent sentient entity with a twisted sadistic sense of humor.
- Or the child is Author as in the Saber that Ayaka summons in Fate Prototype. His Excalibur is an upgraded version of the Caliburn when it came to him as it sensed that he is the last Pendragon because Gawain and Mordred, the only other possible heirs, are dead. He lacks all that angst Saber had because he grew up under Henrietta's kingdom. When he becomes an Adult he is dragged to Camelot by a reverse summon. This is where Caliburn is upgraded. He tries to save the broken kingdom but he only gets a bittersweet end. He dies and Camelot falls but he was successful in saving civilization from complete collapse. Other things also support this. First is that he was willing to sacrifice his own wish to save earth, something Shirou would have done. Next he is not as stone cold as Saber and acts more like Shirou, he kindly says "I will protect you", you know he got this from his father's old personality, last is that he has this 13 seals by the round table. This is because he learns from Louise and Siesta that some people fear nobles with too much power so he asks for the seals to be placed to not be feared by commoners. As for Ayaka, Archer in canon is proof that heroes summoned by the Grail come across time and space, so an alternate reality called upon him with the sheath of Caliburn the first version of his blade.
Shirou and Tabitha hook up at the end.
- A quiet yet noble royal, slight of build but incredibly powerful. One with a connection to dragons. And who swore to act as his Servant. Who could be more Shirou's type?