You can't sit in row 30 on the sides with the 5 year old over by the exit doors. Correct me if I'm wrong, but a five year old can't be in that row. You can split up and two get the exit row and two say the row behind or something like that. You get the good seat and everybody else can fight over the next row.
I think two and two would be better then four across the middle, but if you go for the middle make it a bulkhead, there is a bit more room (30 and 17). Besides that you eat first.