The latest catalogue of the eggs that I am aware of is IMPERIAL EASTER EGGS [Christies 1997] by T. Faberge, et al. This does indeed reclassify some of the eggs as Faberge but not Imperial. Namely the Resurrection egg. This differs somewhat I think with FABERGE [Rizzoli 1979] by von Habsburg-Lothringen, et al.
There may very well be something newer, I had pre-ordered the Sotheby's catalogue, but, alas, that is not to be.