One question I have, and I'll chalk this up to a continuity error on the part of the BBC, is why was Orson wearing a space suit from Sanctuary Base 6. If you don't remember SB6 is the space base on the planetoid in orbit around a black hole that was seen in The Impossible Planet/The Satan Pit. The exact time period those episodes took place in isn't given, but based on the Ood involvement, it can't be any earlier than the 40th century. The Doctor said Orson was from 100 years in Clara's future, so there's no way he could have gotten a space suit from that time period. Also, in The Waters of Mars (which takes place in 2059) Steffi Ehrlich said she had "never seen anything like it" in reference to the Doctor's space suit that he got from SB6.
So this episode was technically a multi-Doctor story what with appearance of the first Doctor as a child. Now if you're wondering if this really was a younger version of William Hartnell's Doctor, in The Five Doctors, Peter Davison's Doctor confirms that he is indeed the fifth. Also, in either The Three Doctors or The Five Doctors (I forget which) William Hartnell's Doctor claims that he is the original. However, in The Lodger, Matt Smith's Doctor claims to be on his eleventh face, so this may not stop Steven Moffat. The thing is, creating an extra past Doctor is only a good trick once. Moffat would probably face a lot of criticism if he tried to pull it again.
Now, the Doctor seems to think that Orson had some connection to Clara's life. Before anyone goes saying he's Clara and Danny's great-grandchild, I just want to point out that <SPOILER>Danny gets turned into a Cyberman in the finale</SPOILER>. The connection is more likely through the toy soldier and Clara's interaction with it earlier in the episode. However, I may just be saying this because I refuse to ship Clara with anyone other than myself.
