no.
im only using 1 case study which can be adapted into the 5 topics. i would focus on a global business for ur case study.
the idea of having to have more than 1 case study for every topic is overrated. a student achieved a band 5/6 in 2002 for the last question and only mentioned a line of his case study.
u only need it for the extended response in the last question. well thats for ur main case study. u might need to use like a little case study in each.
im pretty sure financial wouldnt b in it coz its usually belong to short answer questions with all the ratio n craps. im betting 80% on global & something thou...sux ><