That's more what I expected 
SecondComing, I like Wilbur, don't particularly like William, Wilfred or other Wil- names. However, I know from experience that most people, including me, are far too lazy to use someone's full name, so it will get shortened (I don't particularly like "Roof" but that's what DS1 ends up as a lot of the time); plus, as someone else said, it gives him the option of a relatively common nn if he really hates his full name.
Mopsy I've known a Will(iam) for most of my life and he's never been called Willy, though does get annoyed if you call him a silly billy.
Yes, Wilbur is a pig. Tabitha and Felix are cats, Jemima is a puddleduck, Tom is a kitten, Peter and Benjamin are rabbits and Samuel is a rat. This does not bother me :)
ChippingIn It would make it quicker when calling them in for tea though 
Sounds like Mortimer is winning in the same way the Tories won the last election
They are all real recognisable names. If I was going to try to be yooneek then there are much much worse names I could use