Hi,
There aren't too many options in Lusaka from what I can gather. If you dont want to stay at Chachacha or Ku-Omboka then you could camp at Eureka Campsite.
Eureka Campsite. Other than that there are the usual range of pricey international hotels and cheaper, locally run places.
As for Katanga, I dont know anyone who's been there recently but the following sites are quite helpful:
UN NewsKatanga NewsI hope this helps, please let us know how you get on,
Have a great trip

Sian