[Jim McDougall]

This is an incredibly interesting item, and in my view is likely an armor from Benin, in West Africa. These kinds of armor were worn by warriors of a kind of society known as a leopard hunting guild (in western perception). The leopard is highly feared in these regions, and typically the armor worn is a kind of cataphract style (overlapping scales) of the scaly anteater (pangolin).

However, the helmets accompanying these were often of crocodile hide, so it would seem possible that material would be used as well. It is noted that occasionally the materials might vary, and these are depicted iconographically in many figurines and art .While noted as a 'hunting' society these warriors were soldiers as well and these 'totemic ' identities of animals and reptiles seem prevalent in other West African 'societies' .

There was a 'crocodile society', whose activities like some of the other societies were pretty nefarious.

It could be this armor might have been from such a group as the 'crocodile society' as the members were believed to become crocodiles during the duration of activity.

Most armor of hides etc. in earlier times were strictly of animal material, along with magic talismans and imbuements which were foremost apotropaics.
It seems quite likely that with the advent of firearms, the addition of an iron under covering would be deemed reasonable in the latter 19th c.

So I would say, West African warriors cuirass, probably Benin, late 19th c.
The cross is a common holdover in West Africa from the Portuguese who deeply influenced the tribes. Rather than religious affectation, it was seen more in a talismanic or magic sense.