You can use the NB10 in this case for the AR-M165. This one is still available. Make sure you make a notification on the machine so that no one will think it is an NB3 while there updating firmware. We tested it over here and the M165 can scan(to email) en print.
I don't know that for sure. The AR-M207 is not a type what we use in Holland. I only know that the Netwerkboxes basicly are all the same (NB2) and only the programmable dimm is different. If it doesn't work you can try to place the right dimm in the NB10 (VHi29L96044QS for USA) and move over the right firmware for the NB3 on this one.
But again we only tried it with an AR-M165 and it still works. Onestly i never tried if it will work with sharpdesk, but scan to e-mail is no problem.