I have read in some posts here that folks describe in their accompanying assumption doc about how each non-functional requirement(NFR) is met in their architecture. Is it required (in the sense to make the doc complete) to detail out how each of the NFR is met or just highlight some of the common ones like scalability, performance etc? Another thing, do we also have to propose a hardware or software load balancing solution in our architecture?
Yes and NO. You may or may not need to mention about the NFR's in the assumption doc. Whether you detail in length or just highlight it, it depends on how crucial you consider them to be in the whole architecture. The part 3 of the exam will test some NFR knowledge so its well worth planning and documenting it within the assumption section. load balancing holds a critical place in overall J2EE architecture design and is hence recommended as well.