I think it goes something like this:
Doudna, et. al. were the first to discover and describe CRISPR in nature.
Zhang, et. al. were the first to successfully develop ways to edit genomes with it.
Mojica is generally considered the "discoverer of CRISPR". Douda and Charpentier took that knowledge and made a specific genome editing system based on bacterial enzymes (Cas9) and demonstrated it working in bacteria. Zhang is generally considered the person who made it work in eukaryotes.
