Have you priced out the cost of getting connecting cabins in lower categories (oceanvies, navigator verandah, verandah) in comparison to the suite? Then you can make your own suite, and it gives you greater separation than in the 1BR suite alone. We found that to be much cheaper than booking a suite in advance. With such young ones it's not quite as economical if you are a party of 4 older folks or kids, but since they're charging for babies now its not quite as much of a penalty as it was when they were free.
If you still want the suite you can look into upgrading at the port (though having 2 rooms is a bit of a disadvantage then because you end up holding an extra room or throwing it away since you only upgrade 1 room) and it would be much cheaper than booking the suite in advance, though it is not guaranteed.