>> 2) As this is a low discharges application, is NiCad or NiMH the most suitable, or something else?
Depends how low - take a look at Alkaline or Lithium. Rechargeable
cells are not good  for long-term (>1 month) discharge.
>If you plan to sell in Europe, NiMH is your only choice. 
What makes you say this ? Nicads are still more readily available than
NiMH, in the UK at least, and are still being used in new products.
I recently heard a comment  (don't know how serious) from someone that
ni-cads are greener than NiMH as they are more amenable to recycling!

     ____                                                           ____
   _/ L_/  Mike Harrison / White Wing Logic / wwl@netcomuk.co.uk  _/ L_/
 _/ W_/  Hardware & Software design / PCB Design / Consultancy  _/ W_/
/_W_/  Industrial / Computer Peripherals / Hazardous Area      /_W_/