Could you hire a bouncy castle or 2? Would keep all ages entertained. Activity packs? Music and lights, let the kids dance around x
I had a bean bag throw, velcro darts and a ring toss game all out on the lawn for mine! Appreciate it was August though, but they could all be indoor games too in a safe room ☺️
Meet up at a toddler friendly park with a toilet, seating nearby. Some bubbles or a bubble machine, a couple of balls, a stomp rocket and probably cupcakes, or a box cake, fun inflatable toys, some toddler friendly finger food, pizza and cold water/juice and if course a bit of music. Kids can do their thing, adults can just chill and then everyone can go home in like 2hrs and take a nap 😆
Go old school and do pass the parcel, musical statues :)