first time organising kids party, please help

[tailsandscales]

Hi my soon to be 5 year old wants a proper birthday party with magician. I've just booked a hall and magician - he's seen him elsewhere and loved it so I've booked this specific guy. He's going to do everything- magic, then disco/games after the food.
We need to organise the food - any advice on this welcome!!
We are inviting the whole reception class. How far in advance should we do this? And how - Facebook, email, written invites sent to school?
Would it be a bad idea to invite other friends from outside school?
Also, the magician is just 1 person. What happens if he can't come for any reason?? I know I'm worrying about something that might not even happen but what would we do??

About 4 weeks in advance, paper invites to the class, but if you're in contact with any of the mums I'd let them know directly too. Of course you can invite other kids but just a word of caution, if you invite somebody that doesn't know anybody else at all apart from the birthday child, it's possible they might be a bit left out as the birthday child tends to go off with their school friends. Draft in another few adults to stay at the party and help as quite often at 5 people are keen to drop their kids & go!

Two or three weeks in advance for invitations. Paper ones are fine.

Has the magician given a max number? If not it's fine to invite out of school friends.

Keep it to about two hours max. Activity/game as kids arrive, magician, party tea, few games while you clear up tea, get the party bags out to signal home time.

On invitations make it clear that you can't accommodate siblings and that you need a reply by x date.

Thanks for replies. Will see how many kids can come then maybe invite some others who know each other. I hadn't even thought about there being a max number for the magician. I will ask him!