Psychologically, Lusofonia is a unique reaction of human to identify, or gard himself as being a special group that: (1). He or she has a far heritage link to the target group, (2).Offers an especific social strength or identity to the individual by joining, (3). There is aspecific psychological healing by joinig the group to overcome other short- comings. Overall, the sense of petriatic and loyalty in these groups are distigushed, and could be used by other groups in different dirrections!
You may want to look for Michel Cahen and Elísio Macamo. They're not philosophers though. In general terms, there's a widespread albeit not mainstream worry about the neocolonial implications of Lusophony in terms of the dynamics of cultural production and circulation, from PhD centers to mass media, in relation to either Portugal either Brazil. That showed up in the last Conlab two weeks ago in Lisbon. Nonetheless I believe people haven't started to write about it in a consistent form. If you intend to do so, I would be glad to read your work. Good luck!
I hope it 's not too late but I suggest that you read Miguel Vale de Almeida:
Portugal's Colonial Complex: From Colonial Lusotropicalism to Postcolonial Lusphony. Link : http://miguelvaledealmeida.net/wp-content/uploads/2008/05/portugals-colonial-complex.pdf