As far as hanging out with Christian kids: I don’t look for that as a standard. We have a kid who lives nearby, goes to church twice a week, is in the worship band. He’s thrown rocks and baseballs at my kids’ heads, stolen their scooters and is mean to them when he thinks I’m not looking and nice to them when he knows I can see. He’s a Christian.
A Christian can be wonderful or not.
The standard I teach my kids isn’t about looking for designer religious labels but about looking for qualities of love and kindness and making things right when they’re done wrong. If that shows up in Jewish, Christian, Buddhist, Athiest, Whatever-ist, I’m good with it.