Have gone away a few times with a baby and have always brought my own nappies, baby food and formula with me. Not always that easy to find things when abroad and Formula may be different and with heat etc. you dont want to do upsetting the baby by changing formula.

Just get one suitcase and put all the baby things in and remember you only have to bring it one way and it will give you extra room for coming home. One year I just brought one large pack of nappies, wrapped them in a black sack and labelled them and allowed them go through as a piece of luggage.

Hope this helps.