Never heard of Gertrude the cow. Isn't that Ermintrude?
I don't think Wilfred would automatically become Willie but as that is my father's name (his preferred abbreviation of William), I wouldn't have a problem with it.
Lucien is fine but reminds me of the rabbit-breeding Carla Lane character. I also like Lucius but am put off by the Malfoy connection. Lucas is ok but is becoming chavvy.
Lilias is no more tampon-y than the ubiquitous Lily and has the benefit of being less common and then of course, there's the Scottish connection too. It's difficult to find a pretty Scottish name and I wouldn't mind giving a nod to my Scottish ancestry.
As I said earlier, Lucifer Jesus is fairly unlikely anyway as I can't think of a suitable third name. I wonder if forumites would automatically assume I was joking if I said I was considering Mohammed?