The first thing you need to do is make sure you get the baby's passport asap. So you need to register the birth promptly, and get the forms off straight away.
Your baby might be older than that, if they arrive early, but probably won't be less than 8 weeks. If the delivery is straightforward, then you can expect to be largely back to normal by then (the post-delivery check was always at 6 weeks). But you might not be the same size/shape, especially breasts, though if you breastfeed they might gphave stabilised by then.
You simply can't know what temperament your baby will have, and whether they will be sleeping well. If you're flying, you probably can't take a travel coat so you will have to check carefully with your accommodation what they can offer.
You'll need to take enough nappies to cover journey (inc delays) and remember that nappy cream and premixed formula count as liquids for security. So it's seriously easier to take a BF baby (I took my youngest on a flight when only 6 weeks old, don't think I'd have managed if I'd had to deal with bottles)
Take plenty of clothes and put hand wash liquid/powder in as well.
You might like to try to rearrange the holiday to a destination with a significantly easier journey, if that sounds rather daunting.