1. all depends on their requirement. 2. don't think you will be join to your expected positions/roll Interview will be quite good 3.Just be confident you will get the offer 4.If they want to take to their requirement ,your domain person will come and take your interview and he will ask the questions which you cant tell.. then he will tell you you may not fit for this position but you have similar other position ..likewise they will convince you ..I would recommend go on working day for interview if you want the position which you like ..if you want just any position go for interview on weekend.