For IITs not NITs

there are around 27-28 ques in part A(40 marks - includes 1 as well as 2 markers)

in part B there will be minimum 4 questions of drawing (60 marks)

you will be asked to leave the backpacks outside the class you will be giving your exam. So there's no issue carrying a backpack

it varies every year, last year it was 58/100 for bdes, on avg its usually around 45 to 55

1:1.618

idk

Prepare for UCEED, the past year question paper and format is quite similar for SEED. Also keep creating portfolio works which can include art works and designs. Practice drawing topics thoroughly.