Hi Nick
Reference the French, I agree, although I have undertaken a fair bit of research on French Air/Infantry co-operation (which I will have to review when I have time) from many documents that are available due to correspondence between the RFC and the French plus the translations of French documents that the US undertook. This role is not covered particularly well, if at all, in books on the French air arm.
Bomb racks etc. were always a responsibility of the squadron to fit, even in August 1918, as is clear from documents of the time. Another example is Klaxons, that are fitted in various locations on aircraft, it was down to the preference of the squadron.
Mike