children's party virgin - help please

[bunny3]

Ds has his birthday party in a fortnight. 30 children, school hall etc. We have always done wacky warehouse type parties till now where food is all done for you. I have just realised I have to organise food myself this time and am in mild panic.
Answers to the following burning questions will be hugely appreciated:

mini pizzas or hotdogs or sandwiches? If sandwiches, what are the most popular fillings?

should I bother with fruit/cucumber sticks etc? (I am sure these are put out just for effect)

food on table to help themselves or dished out by adult helpers? Or party boxes??

juice cartons or plastic cups that can be refilled by big jug of squash?

biscuits/cakes or both? same time as savoury food or after?

crisps - bags or bowls?

see I told you they were burning questions!

ooo my second top tip (learnt the hard way, this w/e in fact) on no account try Annabel Karmel's jelly boats in orange skins. You end up with holes in the skin, the jelly escapes, and if, like me, you start making them an hour before the party they're not going to set in time anyway. It would probably be advisable not to try anything my AK in fact.