You know that every single argument can be seen in the context of calvinist theologians wanting to avoid the implications of their own theology.....some saved, some damned (L in the above Calvinist Construct.) You want a concession that these scriptures could mean that "infants are all elect." There are no scriptures that say that, but I will agree with that kind of leeway in interpreting scripture is acceptable.
You also realize that the scripture above, if I'm allowed to use/interpret scripture the same way as they use it above, is also legitimate support for the belief that Christ sees infants/children as innocent.
The question is posed incorrectly. It should ask if the sacrifice of the Son is sufficient to cover the sins of all humanity.
The answer is yes. It is sufficient to cover the sins of all humanity. Why doesn't everyone come to the Lord?
Because they choose not to, given that 2. - - Christ provided a universal opportunity by dying for all men and for every man such that ALL those who turn to him as true repentant believers are saved. (See Arminian construct above)
Nope. You can use them for the belief that those who die in infancy, are going to heaven.
David and his infant son were both heaven-bound, but David's infant son was no more "innocent" of Sin than was David. (Scripture nowhere teaches that either was "innocent" of sin).
Death passed upon all men, for that all have sinned. The fact that all are born mortal, is juridically founded upon the fact that all have sinned. If Infants have not Sinned, they would not be born mortal. If the were not sinners, they could not die in infancy. Death passed upon all men, for that all have sinned.