Jane remembers Mr. Fisher-King's suggestion when she asks for the "Curdie books" from the manor's library. They include The Princess and the Goblin and The Princess and Curdie by George MacDonald, an author who had a profound influence on Lewis. Phantastes was the first book by MacDonald which Lewis had read. Jane also asks for Mansfield Park by Jane Austen. I think it may be safe to assume that Jane has already read Austen's Pride and Prejudice and wanted to read more by the same author. I can only guess why Jane also wanted a book on Shakespeare's Sonnets. Maybe she desired some sort of love poems as she thought of Mark.
Mr. Bultitude's name appears to be of pre 10th Century French origins. The word "boulter" refers to a chef who cooks meats. Maybe Lewis simply wanted to give this tame bear an interesting name. It seems to remind me of the Christian "Beatitudes" because of it's sound. But I doubt that Lewis intended them as a reference.
As Jane goes downstairs to the kitchen she notices a "stuffed pike in a glass case". To me the carnivorous fish known as the pike resembles the hnakra encountered by Ransom in Out of the Silent Planet. I think this could be in inside joke for readers of the previous two novels in this trilogy.