Better question what age kids... At 11 I could barely drag a sunfish... but the all styrofoam Snark was downright carryable.
If you throw a beach dolly on many small boats, the kids can move them themselves TO the water, but they can be a real bear for them to flip if they turn turtle. I sailed a sunfish for a season at age 10... turtled it once, and I wasn't heavy enough to turn it back over. My snark... I'd turtle it on a hot day just cause I could...
If the kids are always 2 up, then you can get away with larger boats too.
But I sailed them all as a kid...
laser, sunfish, wildflower, sunflower, snipe... zuma
Hell I bought a Zuma a couple years back (4?) just cause it was cheap, $200. Sailed it in 15+ knots winds with 50 degree water (and NO I didn't flip it), but I decided that I am now just too old to deal with trying to flip a boat in cold water. It's been keelboats since for me.
My personal favorite for simple rig, fast, and will grow as the kids do is the zuma. Open Bic looks pretty cool too. Hard to turn down the Opti too, especially if there is a fleet, and we're talking younger kids.