Important distinction: Only one side is using "belief", and that is the one that has subscribed or invented themselves the idea of life before or after death. Zero evidence supports this. I'm not saying it does or does not exist, but it's a weak point to bring up.

You could just as easily invent the idea of children being literally us, reborn, to justify their creation. Or that children are literal currency in the after-life market.

As for your second point, I think it's the first strong natalistic argument I've seen here! I don't agree with it any more than I agree with the antinatalism folks, but I appreciate the optimistic counter to all of the pessimistic points being made here.

In the end, I guess I remain of the opinion that this area of life (like countless others) is a gray area. I don't see either extreme as logically moral or immoral without more information being applied on a, case-by-case basis