Question

I feel like juice and cupcakes isn’t something one year olds would be given at daycare?

You have to speak with the daycare about their food policy. I wasn't allowed to give the yogurt Tubes I bought and my son didn't like, even though they give them out there for snack

I wouldn't personally only cause most people don't give their one year olds alot of juice or sugar, so it won't probably go to waste. Also it would seem unfair for some kids to get a treat and others none, if the parents are okay with those being given.

For safety reasons daycares tend to have policies in place regarding food. Also, some children have food allergies and sometimes they forbid food brought by parents. Then you face parent's choices and as you have seen, some don't like to feed their children cakes or juices. I have heard of some daycares where they are quite relaxed and allow in anything made by anyone. On this case, please still mind children with food allergies as you don't want to leave them out, nor to cause them harm. The best way tk go around this is to ask the staff in your daycare and see what they say.

Would you plan this just for your baby or the whole class

Not for the first birthday. Just celebrate at home :)