Hello,
Did you ever receive a reply to this? I am just seeing your message a year later through doing some research. I am currently researching "my bagnards" as well. There is an active genealogy group in Noumea that may be able to offer advice on the kinds of records available in the archives there. I can send you the information for their listserv, and you could perhaps inquire that way (in French). If you are still searching, feel free to contact me through ancestry or my website below.
I'd appreciate hearing how you obtained the dossiers from the archives in France. I was told by family in Noumea that they would respond to a written request, but they told me that I would need to hire (a very expensive) local researcher to copy them for me.
Cheers,
Sharon
www.twocaledonias.net