Yes, I would agree that this is a problematic passage to base the conclusion prooftexted to it.
My interest in the issue was to try and form some context around @structureoftruth’s 6th point above. It would however seem that 2 Samuel 12:23 forms a rather less than perfect landmark or point of reference for this.
This also means that if there is an inconsistency on child salvation, it will not be clear whether it is due to any incoherence of the underlying eschatology or simply that over-reliance on this prooftext has distorted thinking on that narrow issue.
This means that I must look further afield for useful context.