1. when should I send invites? some will be going to the kids at his preschool and I don't know their parents, is it still acceptable to invite these kids?
we are having DD's party the last weekend in november and have just sent her invites out now, purely becasue of all the xmas stuff that will be happening at that time of year.
cant help with the preschool friends DD isnt old enough yet! lol....

2. how long should I give people to RSVP?
we have given a week, mainly because its family and a couple of friends for a BBQ, so not a massive party...

3. I want parents to tell me if their kids have any allergies, well before the party date, how can I word this on the invite?
what about something like " please call me and notify me of any allergies/intollerances your child has so we can cater for them"

4. what do I do about people who don't RSVP? still cater for them?
i tend to allow for a few that ahvnt RSVP'ed just to be safe....

5. I will be happy if siblings and parents of the invited children stay for the party, how do I word this on the invitation?
another simple "please let me know if so and so's siblings would like to come also for catering purposes....

hope thats helped!