Don't forget the Irish volunteers that I mention as well (especially the chapter on the Irish Jasper Greens of Savannah, GA). Thank you for the recommendation. Your other three suggestions are great as well. If a reader wants to get a bit of the Mexican side of the war in an English-language work, they should try Irving Levinson's "Wars within War". I apologize that I do not remember which press he got it published with.
Tyler V. Johnson