There are two c's for a reason, as Andrew Higgins made clear in the The New York Times back in 2014. The Romanian hacker whose real name is Marcel Lazar Lehel chose the handle Guccifer with a famous Italian designer in mind:
[He] signed off as Guccifer (pronounced GUCCI-fer) — a nom de guerre coined, he said, to combine “the style of Gucci and the light of Lucifer.”Language lovers will note that even though this explanation settles the matter of how to pronounce the hacker's name, it does so only by providing a deeply dissatisfying etymology.
The problem is that the /fer/ part of Lucifer has to do with carrying, not illuminating. Lucifer does mean "light bearer" (as Guccifer plainly understands), but the reference to light is embedded in the /luci/ portion (derived from lux, which is simply Latin for light).
Since the /fer/ part of Lucifer conveys bearing/bringing/carrying, Guccifer's name really seems to mean "bearer of designer goods."
So when you hear newscasters pronouncing the first syllable of Guccifer's name as "goose" (rather than "gooch"), the way to keep yourself from becoming annoyed is to pretend that they are intentionally mispronouncing his handle to reproach him for his own sloppy approach to etymology.
Whether the same pronunciation should apply to Guccifer 2.0 is a more complicated question--one that I think Guccifer 2.0 is better suited to answer than anyone else. So I posted a comment on the Guccifer 2.0 blog asking the hacker to settle the matter. I'll update this post if I ever see a response to my query.