If unprovoked, certainly, those actions go beyond the limits of the laws of war of the time as outlined by Marten and Vattel.

The only suggestion - to strengthen any paper (not for me or this forum) - would be to improve on the evidence that (1) the local avoided "resisance be offered" or they held out "menaces" to use James's words, (2) the actions of any Portuguese renegades and (3) the French view. This last as to why and to what extent they acted. All to understand and explain (not to justify).

All this may be easier said than done for I suspect appropriate sources may very limited indeed.

As an example and if it occurred (as in many American movies about the range wars in the West that a rancher started trouble between the ranchers and the farmers), I would doubt any wandering Frenchman (or Portuguese renegade) would write that they robbed some village, those villagers became unset and attacked the next French patrol they saw, and then - going to their rescue - the main body of French pillaged and burnt the village, killing all inhabitants they found.

This said, good luck.

Happy Holidays,

Ralph