Get a travel black out blind
Sunbed clips or pegs are also good for making sure curtains fully join up at night
If you have an extra large muslin blanket take it, by far the best holiday item we have ever used for our DC, so versatile for naps, shade, makeshift clothes when stripped off or covered in sand, distraction games of peekaboo… we don’t go on holiday without them even now and our DC are much older now
Unless covering your dc up the whole time or in the shade 24/7 then soltan kids sun lotion is the only one that our dc have never burnt with, particularly the once daily. Think they do a baby version too
Talc powder - amazing for getting sand off!
Unless you have one already or will use for other things, you don’t need a travel buggy, your normal pram or buggy will be completely fine but recommend a buggy bag for when putting in the hold for the flight, can get them on Amazon
At that age - if I had my time again I would make full benefit of going out in the evenings to nice restaurants, for drinks etc with baby in tow, so so so much easier than it will be in years time and places you can take babies too but can’t necessarily take toddlers or young children once they are walking and talking, if I had known that at the time I would have maxed it out more!
Microwave travel steriliser bags are good, we have also done many hotel sinks with Milton tablets in!
Take calpol and teething stuff!