I think this concern over "having enough points for our kids" is often a little shortsighted. It SOUNDS like a great and fair idea at the time, and its a generous thought. But kids don't always grow up to want or be able to afford regular
Disney vacations.
I think the best way to avoid regrets is to look at this as a "ten year" thing. Don't worry about what happens in 2042 (or whenever contracts expire), whether you can will them to your kids (you can). At the same time, don't assume you need to buy BLT to be near the Magic Kingdom because that is where your three year old spends all her time. You'll blink, she'll be thirteen, and wanting to spend all her time at Typhoon Lagoon.
If you can get value out of it over ten years, its probably a pretty good deal. If you can't, its probably not a good deal. And if you are looking at it as something that is going to bring you joy for fifty years - I hope it does - but your crystal ball is way better than mine.