Answers to your questions:
1) yes CS exams are easy compared to CA exams. these are purely held on direct questions based on their own ICSI's module contents only. ICAI just confuses students in exams by asking questions in different manner whose correct answers even president doesnt know. This is the basic difference between ca and cs exams. ca exams are aimed to fail the student, they arrange papers in such a manner that atleast one paper in a group is difficult, everything is unexpected. However ICSI doesnt do that mess. CS institute is very clear on its objective of selecting hard work. And people giving ca exams find cs exams easy because these exams are direct and streight forward.
2) Yes 15 months training is mandatory. Even i am also planning to do it but thats not the case that, vacancies are not there. your frnd might not have tried in a full manner. there are lot of companies and all most every company has vacancies. Getting company for training is not a difficult task, we have to understand their procedure only.
3) Requirement of CS is as eqal as ca. difference is that, there no marketing for cs. only ca's name is just famous nothing more than that. just go to naukri.com put 10 years experience and a member of ICSI and search, see you get same packages even higher packages than a ca.
And one more thing, telling u from personal experience, CA ka koi bharosa nahi hai, bt CS ka bharosa hai. definitely pass ho jata hai. first complete cs then give any number of years to ca. there would be no problem.