Yeah kitten/cat. Easy to care for. Self cleaning cat boxes are fabulous.
Cats are good first pets IMO… they live long life’s (less heartbreak) and there so easy to care for.
Dearly Presents I agree with Lillian Murray . A rat makes a wonderful pet , only downfall is that they only live a couple of years.
My daughter and 7 yr old grandson decided on a fish tank and a fish of his choice.
Most people don’t know it but guinea pigs like leaving outside in your yard under the porches. Me and my sister had some but what happened to him a nosy dog came in fence and killed one and then some little kid come by and stole the other one.
Get a chicken and let if free range. They can collect the eggs and clean the coop to learn responsibility and they get a pet that poops breakfast. It’s a win win. 
Get guppie fish they have live birth. No eggs. Seahorses are real cute too.
Guinea pigs are cute sweet and easy taken care of.
How old are your kidds
Go small. A mouse or like!