If i were to have multiple arrays declared in my session (Around 30 Array List at the max, Each array list is of size 56) will it be some kind of performance hit ?
This kind of question is impossible to answer. Whether there would be a performance issue in any scenario depends so much on factors other than the code. What else is the server doing? What is the hardware configuration? Even what the OS is.
In general, the amount of data you are talking about is peanuts. But how many simultaneous sessions are you expecting? 2, 20, 20,000?