Where should I go for online information on animals endemic specifically in Mozambique?
Here is a large list of animals (sorted by guilds) that can be found throughout Mozambique.


Each animal in the list is linked to a page with picture and information!

Wikipedia maintains a few lists of animals found in Mozambique.


See here for  a list of mammals (sorted by order). 
See here for a list of birds (sorted by order). 
They also have 2 lists for mollusks (fresh-water, marine) and 1 for plants. 

Gorongosa's own website provides a list of common animals found in Gorongosa:
http://www.gorongosa.org/explore-park/wildlife
As user Sudachi mentioned in a comment below,  iNaturalist and GBIF also have lots of well-managed species lists and observation data.