Did you end up buying the amby hammock? If you did it might be worth taking it with you so Tariq can sleep somewhere familiar. Virgin Blue counts porta-cots as 5kg regardless of thier actual weight.
I always try to offer something to suck on take off and landing. I try to get a window seat and get DH to sit between me and the aisle and read a newspaper so that if bubs decides to yank my top open I don't give the whole plane a look at my boobs.

I'm sure you'll have a great time visiting your family. I've found that when I've travelled overseas and interstate to visit family that in some ways its easier than at home because I have so many people who want to help where as at home its just me.