As they’re apartments, what is the outside space like? Do they have a terrace/small square with railings? If so, I would be mindful of having something there - like a blackboard on the railings with chalk/or chalk markers.
Info to local GP/late night pharmacy.
Second child size plastic plates, cutlery and glasses.
You
mentioned a steriliser, maybe say a generic one is available on request as they take up too much room otherwise.
Stationery and paper for kids.
A plastic seat which you can use at the dinner table for toddler who are out of the high chair stage, but still not big enough to use a chair.
A two in one toilet seat in the main bathroom, not en-suite, so you can pull it down to accommodate smaller bottoms. Plus a kids step stool in the bathroom too.
Easy to reach hand wash attached to the wall or something which is not a ceramic thing that is easy to knock over.
Bath towels, tea towels, plenty of dishwasher tablets and proper cleaning equipment.