I think if you take backup into consideration, you will need either 2) or 3) on top of enough 1).
The Idea of hauling my 2.2kg Laptop along with all my other gears give me nightmares.... :sweat:
On any standard dive trip..... my diving gears will go into the plane at 18-20+kg...... not including clothings and other stuffs (DSLR camera + lense + tripod = HEAVY).......
Last thing I want to bring is a laptop...... :sticktong