Pesach party rules

I'm starting to Google birthday cakes and party ideas which are kosher for Pesach. This year Son's birthday falls on the second day of the eight-day festival. It's a tricky festival as by the time Pesach begins all the bread and biscuits in the home will have been replaced with matzah and anything edible without an explicit "Kosher for Pesach" sign should either have been given away, thrown away or hidden in well taped-up cupboard (I don't think the taped-up cupboard would get a kosher stamp from my Rabbi but in our house right now it's good enough). We usually do a good clean of our fridge, stove and oven at this time, but we don't pick into the crevices with a toothpick and torch. We partake in the first and second night meals complete with in-depth readings, story-telling and songs but may work on days when it is not permitted to do so. These no-work days are the first two and last two of the festival and that's where the next complication regarding Son's birthday will arise; his birthday is on one of these days. Even though the prohibitions regarding work aren't as strict as those governing the Sabbath, I don't think I can arrange a party at a non-kosher venue especially if there are things like music and money floating around. A picnic at the botanical gardens with matzah sarmies and flourless cookies might be fun, but I don't even think we're strictly allowed to drive on that day so some of his friends won't come. Maybe his cousins won't come! I might even get into trouble for handing out invitations at our semi-religious school... I just don't know!