The key issues will be time difference & heat. I took eldest DD to Trinidad when she was 6 months to stay with my ex partners family and if I’m honest, it was hard work! The advice is to try and adjust their sleeping patterns gradually before you go to help fit in with the new time zone. Speak to the customer services department at the airline and ask what assistance they can give you and how you would secure a bassinet (a basket which attaches to the wall on the plane where you can put your baby). I’m not sure you can reserve these now and it may be pot luck!
For the plane take spare clothes, muslins etc and buy wipes etc after you go through duty free. Take a spare top for yourself in case you get sicked on! Find out from the airline what will happen with your buggy and where it needs to go.
In your suitcase, pack the best sun shade you can find for your buggy, a sun hat and factor 50 suncream. Take some baby friendly insect repellant as well (unfortunately for babies I think the advice is not to use deet based products so it would have to be something natural) and repellant plug ins for the room. If they aren’t fussy about food, don’t bother packing food for them but do if they are! Take lots of light clothes and stuff to layer up on cooler evenings.
As above, heat is the key problem and try and keep DC in the shade as much as possible. A really hot over tired baby isn’t much fun! Though it was lovely to introduce DD to all her Trini family, it was definetely more hard work than I was anticipating and I didnt take youngest DD on a plane till she was 18 months!
Final thing, most Mums get really really anxious & stressed when their babies cry on a plane. Try not to worry too much about this - many of the other passengers will have done the same themselves and will be sympathetic!