That's the whole point...I don't. All that was in the OP was pictures of smiling (Siberian?) children. That they are laughing and playing makes them no more nor less likely to be saved than a child anywhere else in the world. The issue is that there is nothing in the photographs that allows us to judge righteously. Nothing.
There love for their animals is all we need to see that expresses their loving dispositions, don't you think? -- I guess not. What more do you think they need for salvation?
Depends. Do you mean we shouldn't mature but stay in all respects as children? If so, my answer is no. Were that true, then there might be a case to be made that a child as it is is assumed to be saved...and then loses its salvation at some point in time (?). At least we could assume that they get draw away from God as they mature. That would mean we could judge according to appearances...
Seems you can't get off the subject of salvation. Don't you believe there is more to God and Jesus then just getting saved, you meaning more to him than just escaping hell??
As it happens, I was meditating some on that verse recently and I realized that one of the things that makes a child seem closer to the kingdom is their ability to move on and not have to justify themselves. If they are given a gift, they accept it and treat it as their own. So when it comes to forgiveness, a child's ability to get past something and forget it is remarkable. Whereas the older one gets, the more one tends to want to justify one's self and not treat a gift as a gift. So once forgiven, the adult tends to want to repay that forgiveness to make things square. Forgiveness of sins implies a debt far larger than we can ever hope to repay - so trying to do so means we are trying to approach God in our own righteousness. A child doesn't try to do that.
That said, there is still foolishness and self bound up in the heart of a child. That behavior is only a type of what the child of God looks like.
Again, the issue of salvation. I don't get it when the Bible is filled with so much more of what God is after from His creation AFTER they get redeemed.